That slide counters your claims that 10GB is enough and it agitates you.
You cannot provide any insight, other then your own guess, as to why frame rates look so bad or you would have said so.
Therefore, you really don't know what you are talking about. Except feeling some kind of way that shots were fired at the fact that 10GB really isn't enough for a flagship card. As it stands, this is the type of example of what happens when you are vram limited at 4K using RT in an open world game. It's not hard to figure out DLSS's reduce resolution also reduces the memory footprint require therefore you see the increase frame rates. However, again for a flagship card, we should be seeing this already without DLSS.