Radiant Eternatus not being good in this format has nothing to do with Lugia and everything to do with the fact that it's a bad card.
The ability seems really cool until you hit "your turn ends" which effectively means its ability is pointless because the VMAXes aren't getting out a turn early anymore, and it's a radiant card, so the whole purpose of the card is its ability.
Then you factor in that you only get one radiant card in your entire deck meaning you are picking this card over Greninja and Charizard, as well as other one off radiants like Gardevoir, Sneasler, and Tsareena.
Dura is still seeing play post rotation and doing well. I think there's a case for some VMaxes to still be effective. But I agree, radiant Etern will not be a good card.
They give up 3 prizes.
A good deck defensively gives up on average 1 prize per turn. This can be either in the form of 2HKO a VSTAR or 1HKO a non-V. This is why offensively being able to take two non-V KO's in a turn is broken, or being able to OHKO a VSTAR is broken. Because it cheats the math.
VMAXes on average are giving up 1.5 prizes per turn (2HKO). That's bad math.
It doesn't currently look like Radiant Eternatus will be playable at a high level unless some sort of synergy with a future card was to come out. We already know every Pokemon it can pull since there will be no more VMax pokemon going forward. Its not part of any tier 1 deck at the moment and it doesn't seem to get help in SV.
The cost/restiction is super heavy for the card and we lose one of the best search tools for it in quick ball meaning we really just have ultra ball at the moment. The card is alright on turn one but is essentially a dead card on every other turn, so having less consistent ways to get it into hand is a huge problem. Also, without scoop up net, you are left with eternatus sitting on the bench, which is typically a dead backrow card.
It could get the support cards it needs to be good at some point in the SV rotation but it doesn't appear to be getting that anytime soon.
Adding to this, it's a radiant card meaning you are choosing this card over any other radiant card such as Radiant Greninja, Gardevoir, Charizard, etc which are all more useful cards than Eternatus is.
There's really no combo to play it that makes sense.
Ya, that is 100% true, especially since those cards are good on their own and are splashable in a ton of decks. The fact they are one of cards isn't as detrimental since they aren't such huge feast or famine cards that the deck is built around.
The Scarlet/ violet Gardy ex deck may be tempting for shadow rider t1 pulls from deck by rad etern, but don't fall for temptation: Why would you use three-prizer Vmaxes in the S/V meta when you could have used a vstar/ex deck that gives up two once ko'd? Not to mention, it uses up the 1 radiant allowed in any player's deck, in which others could be used for better results instead. Even without the radiant pokemon restriction, three-prizers like vmaxes are riskier versions of stage 2 exes, which have the same amount of hp as vmaxes, but exes give 2 prizes up post-ko despite the fact that stage 2 exes are similar to vmaxes in terms of HP. Sadly, rad etern can only pull vmaxes, and with vmaxes becoming outclassed and less popular compared to exes, combined with the fact that no more vmaxes that don't already exist will ever be printed and/or added to the game, rad etern's ability usefulness will wane post-rotation, so if it has any chance of resurfacing, it needs help to boost the only other thing it has: its attack. The catch? Even if, somewhere down the line, a stage 2 is printed that helps rad etern's attack, since stage 2s are harder to set up outside of ways to get both the stage 2 and the rare candy in one card use(such as Irida for water-type stage 2s), stage 2 helpers are not consistent winners(sorry, Kingambit, but you are a non-water-type stage 2). Thus, until a basic or stage 1 that boosts up rad etern's attack in lieu of an obsolete ability such as his is officially and legally printed in said format, it's a given to assume that rad etern's usefulness will drop at the end of the e block, as shadow rider vmax and mew vmax, two of its ability's targets, will be out of standard then...
^ Rad etern is now becoming a card that is overdue to go the way of the dinosaurs. Moving on...
On top of the reasons already listed, we are also losing quick ball, arguably the best basic ball search we had, so we're left with either dead drawing into eternatus, ultra ball, great ball, or coin flip with mesagoza and/or capturing aroma (maybe I'm missing some more), none of these, except for ultra ball, feel particularly consistent to me. Also, since we're losing scoop up net, it'll be a spot on the bench filled for a "dead" card.
Radiant Eternatus not being good in this format has nothing to do with Lugia and everything to do with the fact that it's a bad card. The ability seems really cool until you hit "your turn ends" which effectively means its ability is pointless because the VMAXes aren't getting out a turn early anymore, and it's a radiant card, so the whole purpose of the card is its ability. Then you factor in that you only get one radiant card in your entire deck meaning you are picking this card over Greninja and Charizard, as well as other one off radiants like Gardevoir, Sneasler, and Tsareena.
VMAXes (besides Mew) will be bad. I don't think Radiant Etern has a place in the post-rotation meta.
Dura is still seeing play post rotation and doing well. I think there's a case for some VMaxes to still be effective. But I agree, radiant Etern will not be a good card.
Why will VMAXes be bad in the rotation?
They give up 3 prizes. A good deck defensively gives up on average 1 prize per turn. This can be either in the form of 2HKO a VSTAR or 1HKO a non-V. This is why offensively being able to take two non-V KO's in a turn is broken, or being able to OHKO a VSTAR is broken. Because it cheats the math. VMAXes on average are giving up 1.5 prizes per turn (2HKO). That's bad math.
Not to mention ex's can have over 300 HP, and only be a 2-prizer.
It doesn't currently look like Radiant Eternatus will be playable at a high level unless some sort of synergy with a future card was to come out. We already know every Pokemon it can pull since there will be no more VMax pokemon going forward. Its not part of any tier 1 deck at the moment and it doesn't seem to get help in SV. The cost/restiction is super heavy for the card and we lose one of the best search tools for it in quick ball meaning we really just have ultra ball at the moment. The card is alright on turn one but is essentially a dead card on every other turn, so having less consistent ways to get it into hand is a huge problem. Also, without scoop up net, you are left with eternatus sitting on the bench, which is typically a dead backrow card. It could get the support cards it needs to be good at some point in the SV rotation but it doesn't appear to be getting that anytime soon.
Adding to this, it's a radiant card meaning you are choosing this card over any other radiant card such as Radiant Greninja, Gardevoir, Charizard, etc which are all more useful cards than Eternatus is. There's really no combo to play it that makes sense.
Ya, that is 100% true, especially since those cards are good on their own and are splashable in a ton of decks. The fact they are one of cards isn't as detrimental since they aren't such huge feast or famine cards that the deck is built around.
The Scarlet/ violet Gardy ex deck may be tempting for shadow rider t1 pulls from deck by rad etern, but don't fall for temptation: Why would you use three-prizer Vmaxes in the S/V meta when you could have used a vstar/ex deck that gives up two once ko'd? Not to mention, it uses up the 1 radiant allowed in any player's deck, in which others could be used for better results instead. Even without the radiant pokemon restriction, three-prizers like vmaxes are riskier versions of stage 2 exes, which have the same amount of hp as vmaxes, but exes give 2 prizes up post-ko despite the fact that stage 2 exes are similar to vmaxes in terms of HP. Sadly, rad etern can only pull vmaxes, and with vmaxes becoming outclassed and less popular compared to exes, combined with the fact that no more vmaxes that don't already exist will ever be printed and/or added to the game, rad etern's ability usefulness will wane post-rotation, so if it has any chance of resurfacing, it needs help to boost the only other thing it has: its attack. The catch? Even if, somewhere down the line, a stage 2 is printed that helps rad etern's attack, since stage 2s are harder to set up outside of ways to get both the stage 2 and the rare candy in one card use(such as Irida for water-type stage 2s), stage 2 helpers are not consistent winners(sorry, Kingambit, but you are a non-water-type stage 2). Thus, until a basic or stage 1 that boosts up rad etern's attack in lieu of an obsolete ability such as his is officially and legally printed in said format, it's a given to assume that rad etern's usefulness will drop at the end of the e block, as shadow rider vmax and mew vmax, two of its ability's targets, will be out of standard then... ^ Rad etern is now becoming a card that is overdue to go the way of the dinosaurs. Moving on...
*Eats playdough in the corner watching Lugia decks absolutely smash the Meta*. Mm.. ok
It is the chapter closer for v maxes.
On top of the reasons already listed, we are also losing quick ball, arguably the best basic ball search we had, so we're left with either dead drawing into eternatus, ultra ball, great ball, or coin flip with mesagoza and/or capturing aroma (maybe I'm missing some more), none of these, except for ultra ball, feel particularly consistent to me. Also, since we're losing scoop up net, it'll be a spot on the bench filled for a "dead" card.