4K 60 FPS target was obvious. Anyone with even a gram of hardware & game knowledge understands this. There's nothing unbelievable about it, in fact anyone with a V64 or a 2070 can go out and test this for themselves, so long as they understand one thing: settings aren't locked to the maximum preset. And also, game development optimises over time. It gets easier to do the same thing with time, as the software knowledge advances.
4K 120 FPS also doable for the lighter esports title & the like. Overwatch, Rocket League, etc.
8K isn't too far fetched either, but I reckon this is more of a spec-sheet feature than anything. Obviously it will have 8K video playback, but it could also have something like DirectML 8K for some games. I wouldn't expect too much on that front.
What's clear is that this console is going to be an absolute BEAST. Now it's up to Nvidia to push RT further for PC, because they're about to get hit in the head with a 10-ton bomb for mass market.