If Nintendo, the manufacturer of the console can't do it well for the console exclusive, then maybe... just maybe... might be that the hardware is at fault?

Switch is hardly competitive with modern phone chipsets with its old architecture.

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.

It's not just triple-A ports that struggle on the Switch. Xenoblade Chronicles: Definitive Edition, which is a Nintendo Switch exclusive remaster of a Nintendo Wii game published by Nintendo themselves, runs somewhere between 540p and 720p when docked, and between 378p and 540p when playing handheld.