8GB will be fine for ultra at 1440p and below until some time in 2027, that's when we can expect to see the next generation of engines and feature sets become an actual thing.You can play almost any game if your willing to turn everything down to low sure.
I hope people buying a card that is selling for north of a grand where I live... are going to be ok with having to turn games released at the same time as their new GPU down to medium settings.
I don't know perhaps 12gb will be enough to handle Medium settings in games coming out later this year and next. Its a gamble though.
Most of the huge VRAM memory usage that we have been seeing lately on launch is because of the vast differences in how the consoles and the PC manage loading assets into memory and how the memory is managed.
Microsofts Agility SDK will help normalize this by taking that job away from the developers and emulating the console memory heaps on the PC.
But usage is mostly a bad porting problem currently, and issues with direct access, or lack thereof, which cause many titles to panic load assets resulting in memory leaks, over usage, and blah blah blah, it's a mess, mostly caused by the reliance on some automated tool sets in the Dev-Kits.