If you don't think 16gb is even worth 80$ over 8gb then how can you at the same breath claim how terrible 8gb are? That doesn't make sense. If you are not willing to spend 80$ to get to 16 then we are in agreement, 16gb won't really change your experience that much to warrant 80 bucks and 8gb is perfectly fine.
And following your train of though, the 5090 is the only cars that should exist. I find it weird people keep defending slow cards like the 9070xt and the 5070ti existing. Nope, 5090 or buy a console. Right?
@AusWolf Since you asked and I just tried the game (oblivion) I have to make heavy compromises on a 4090. Can't use DLDSR (card is too slow), and even with DLSS enabled and Hardware Lumen completely off game drops to the 50s (gpu bound). I have to further tune the settings down or go to dlss balanced (maybe performance?) to get a locked 60. Compromises have to be made regardless of your gpu, modern games are heavy, it is what it is.