I feel like the masses of ram in graphics cards is to make up for their lack of processing power. Games are getting bigger and bigger, but only so that they can cache entire assets to reduce the number of calculations required at runtime.
Nvidia introducing real time raytracing was a huge leap in improving graphics. There is still far more in the graphics and rendering world that hasn't been seen in games just because of how computationally difficult it is, and the fact that it cannot (yet) be done in real time - some of it not even in 1080p - means that there is still a need to push for better and better cards.
I look forward to improvements in the raw processing power of graphics cards, since I feel as though that is the current bottleneck for improvements in gaming.