Bringing back my old argument, the appeal of the console for many is striking a balance between portability and power. Yeah, there can be performance issues, but you can play Zelda/Witcher/Dark Souls/DOOM/Skyrim/etc on the go, and you can't get that anywhere else. Certainly things could be improved on the technical side, but the sales numbers indicate that enough people are happy with it.

I’ve got plenty of original Gameboy games, and they all run at 60 FPS just fine. Developers need to design for the hardware.

Nope, the above still applies. That’s a software failure.

Of course that’s not an argument against improving Specs, but to do that they’d probably launch a new generation.