For a few years now actually. Mirror's Edge 2 for example was released in 2016 and used close to 12 GB of ram at 4K with max settings.
Nvidia went from 6 GB to 11 GB from the 980 Ti to 1080 Ti. The 2080 Ti has the same 11 GB. Going from 8 GB on the 1080 to 10 GB on the 2080 is a very small jump in comparison and that's over two generations, not one.
It makes sense from Nvidia's standpoint though, VRAM won't make an immediate performance impact in games now as you have to be seriously deficient in VRAM space but when you are it has a severe impact on your game. It's planned obsolescence. Of course turing was the same way, zero increase in RAM sizes plus ridiculouslky under powered RTX hardware. It's a win - win for Nvidia and a majority of PC gamers won't care as they seem to be completely fine with planned obsolescence. Giving just enough RAM for current games saves Nvidia money, power consumption, and has the bonus of people upgrading more frequently.
Honestly if I were AMD I would skimp out on the VRAM as well. Reviews based their conclusions on the now and most people buy for now. Reviewers and users don't seem to care if products are pushed to 100% or consider the ramifications of that in the near future. Consumerist culture to a T.