I agree for 1080 p games are getting more and more vram hungry , from what I've seen in modern games so far looks like 1080 p is the sweet spot to max out the modern games without the thoughts that is going to slow the games down to achieve the game's best performance
4k the cards will overheat and distort the video's game play
2k the cards would run fine but , I bet in a yr or 2 you will have to upgrade the cards again next yr so 2k wouldn't help