With that kind of mindset you could practically say that for 3 generations consoles have been buffed up versions of themselves.
The PS5 Pro could've been seen as the Pro version of the PS4 Pro and the Xbox Series are buffed up Xbox One S/X.
No no, this example is totally loable, because Wii U was a desktop console, and Switch is a portable console. It would be like comparing Super Famicom and GBA.
Technically speaking, Switch in undocked mode is weaker than Wii U (base Switch with official Nintendo clocks). Developers always develop games for the base version, like happened with PS4 and PS5, for obvious reasons. Taking that in count, we could say that every single Switch game could be adapted to be ran on Wii U, the only limitation we have to face is the amount of RAM, as I've mentioned before.
You have a clear example with Zelda Breath of the Wild. What happened at the beginning? that Wii U version was the clear winner, because the game was working like crap on Switch. Only patches made it better, but even so, when you compare both side by side there are ups and downs, so there is no clear winner at all. You could allege that the game was developed for Wii U, then Switch got a bad port. Well, I could buy that for a non 1st party game, but not for a Zelda, and let alone after so many patches.
So, having said all of this, you also were not very far from reality, but kind different. PS5 could be considered a buffed PS4 Pro, because if a developer had the money and the will to develop a game from scratch for both consoles, both games would look almost identical. What you would play 1440p on PS5, it would run 1080p on PS4 Pro.
Of course, with new hardware there are new technologies involved, but at the end of the day it's what you see on screen what matters, and if your eye can't differentiate one from another your brain automatically processes that it is meaningless to upgrade.