We are talking playing a current generation console game on emulator with better framerate and resolution than on the original console, at release. So no, it has not always been the case
Well, it's long been the case that a $400 console has lower specs than a $1200+ gaming PC, even in the year the console is released. And that the performance gap gets even wider as the console gets towards the end of its lifecycle.
Part of the criticism here is that the $340 Switch is getting outperformed by emulation on the $399 Steam Deck.
I'm pretty sure it has always been the case that a PC emulator could outperform a several years old gaming handheld. At least if enough interest was there for someone to write the emulator.
I'd say that something which is portable is a "portable" even if you can plug it into a TV. It is strongly power constrained. It is just bigger than old portable consoles. (I actually don't know why they were always so small before the Switch. Perhaps large screens were too expensive. Or everyone thought of them as having to fit inside a pocket.)
