What PS4 evidence are you talking about exactly? And your 2nd point is completley false. People buy these videocards to run games at 120fps. My point was that you would have had to make very little sacrifices with a 6GB 1080ti card and still get a similar experience.
Just look at the last few games launched. All of them have the 2080ti struggling to hit 60 fps at 4k while even 6 GB cards keep relative pace (again idtech 7 notwithstanding).
Lack a performance of the 3080ti will still be an issue LONG before 11 GB is.
Wrong. Most people don't even have 120fps displays.