My PS5 is the best PS4 ever. 95% of the stuff I play are PS4 games....
I'm laughing because remember feeling the same when I got my first PS2 and was enjoying how it upgraded PS1 games.
I have a friend who has a PS5, it's his 3rd console ever cuz he mostly stuck to PC. He did NES, N64, and now a PS5. He's able to enjoy a wealth of PS4 games he missed as well as some PS5 games, though he does note the irony of how Sony exclusives are making it to PC now. And some of those he still plays on PC. But yeah his main goal for getting a PS5 was to have access to PS4 games. He actually hadn't really intended on getting a PS5, especially not during the scarcity period, but his wife managed to snag one cuz she knew he had been looking at them for some time, and surprised him widdit. And he's made decent use outta it so far. I'm glad Sony did the sensible thing with both PS5 and PS4 having AMD64/x86-64 architecture, and made the PS5 able to run PS4 games, as it should. And it runs PS4 games way better than the PS4 Pro does. I had to play
Ghost of Tsushima at 30fps while PS5 players get to enjoy 60fps. Still waiting on the PC version of that game...
My base model XB1 is mostly used for original Xbox and X360 games. I too used my PS2 to play PS1 games a lot (loved those faster load times), and I also played my PS1 discs on PS3 a good amount (Sony's PS1 emulator on PS3 is very good, though of course you'll find better on PC, such as DuckStation). My PS3 doesn't have PS2 back-compat so I've never tried it (that would be handy these days since my PS2 Slim no longer reads discs, and PS2 emulation on PC still has some ways to go for some games). Since Gamecube Component Cables (which come only from Nintendo) were overpriced when new, and massively overpriced since discontinuation ages ago, Wii was the best way to play Gamecube games with Component output. I have a soft-modded Wii, but I am thinking about soft-modding my Wii U and also soft-modding the Wii side of the Wii U. It would be more convenient. That too is great for Gamecube games. Wii U won't play Gamecube discs, but you can load ISOs on them just fine (or so I've heard). It was very convenient that GBA could play GB/GBC games, Nintendo DS could play GBA games (but not the refreshed model the DSi, which ditched SLOT-2 which was the GBA cartridge slot, which was also used for other peripherals like rumble carts), and 3DS can play DS games. Back-compat can be extremely handy, and it's always appreciated when consoles support games from older gens
without you having to purchase those games again.