It's not going to last the whole gen even at that resolution. Current gen games are already dangerously close at maxing out 8GB. I don't think it will be able to fit later next-gen games, even at 1080p. I guess we will find out soon.
Edit: Basically, what i'm trying to say, this is going to be the same situation as the GTX 960 back in 2014. A much more powerful card than the then "next gen" PS4/XBOX base consoles but only 2GB initially, because that was the standard for PCs. That card was shit mid-gen. I had to reduce the resolution below console settings in order for many games to run without VRAM swapping slowdowns. 6-8GB is the standard now but what happens after the next-get blows up?