Nintendo also clings closely to its roots as a toy manufacturer - their primary goal is to build games that are fun to play.
It shouldn't be surprising that their focus on creating beautiful, fun games resonates deeply with the wider populace. I do notice the framerate occasionally dip during complex scenes, but it's such a wonderfully designed game that I don't really care.
It just keeps selling though. Sales have dipped, but not so much that Nintendo is in any hurry.
How many units would the game have sold if Yuzu/Ryujinx didn’t exist? It’s even more jarring when you’re a paying consumer running the game at 720p20 and someone else can quite easily download switch games for “free” and play a much better 4K60 unofficial PC version.
Those videos are all over YouTube and have been for a couple of years now. I’d always assumed Nintendo was just trying to get TOTK out the door, give it time to sell, then announce the new system with a new Mario later in the year.
Also, their own quarterly reports and expectations confirm they aren't launching new hardware anytime soon.
They sold so many switches because of nostalgia and convenience/form factor reasons - switch is the only console in that form factor
They have clearly poured a mountain of design and engineering effort into squeezing every last drop of graphic fidelity and art out of the Switch. It looks really really good. Some of that is having the wisdom to choose an art style that works well on the Switch—a little cel-shaded, not a ton of texture detail. But, also, they really are getting as much detail and graphic complexity as they possibly can out of that little machine.
This isn't some cheap 2D pixel art game that spent their whole budget on game mechanics. It's a AAA game that maxed out their budget along every single axis. They just happened to target hardware with lower specs.