The Switch starts at a lower price point, it's available at Walmart, it's more durable for the average child to handle, and Mario/Pokemon/Zelda are what someone like Warren Buffet might call a "brand moat", where nothing's really going to interfere with that business model.
While i agree, the steam deck is not only a great device but an alternative to piracy for me. I haven't pirated a game that's available on steam more than a handful of times and only once i didn't buy it afterwards. With a resurrection of the demo now, I'll play before i buy like the old days.
I love my Steam Deck. It's literally beside my hotel bed right now, while the Switch is at home with two kids under 10. But:
the docking and detaching experience is frustrating as hell
it is significantly heavier and yet feels more fragile.
it has profiles but not comparably to the Switch in terms of use and UX
and the controller experience is very hit and miss.
It spent 2 months just literally randomly shutting off bluetooth - you had to go into desktop mode and re-enable with a Linux command until they patched it - but that's not even it - whenever it did that, it also disabled the sticks!.
I have multiple entries in the controllers screen - none of which can be renamed or show indicators as to which controller they are - where every now and again the Deck decides sorry, I don't recognise that controller anymore. Please come walk across the living room and awkwardly stand in front of the telly pressing buttons on the Steam Deck's face to re-pair things.
Oh and controller layout schemes are a cool and powerful feature but way too complicated for me to explain to an 8 year old.
If "I just want to pick up a controller after work and forget what Philip in Marketing said he thought the project was going to look like", or "I want to buy games once and share them with my kids" or even "I'll throw this in my bag to kill 20 minutes at the waiting room" are factors, the Steam Deck is very much not superior in every way.
Again. Love my Deck. Almost exclusively buy "Verified" games now. Halfway through a Nintendo game that somehow is easier for me, a software dev to find ajd emulate on Deck than on a Nintendo console. But the Switch has been a remarkable console to have in my living room. The first console I bought (actually now that I think of it, that my wife bought for me) since Wii and before that since PlayStation 2. I'm not really a console player. I have 1000+ games on Steam. Still Switch excels at many things and the sales figures should make that obvious.
The switch offers a console experience. Everything just works and works well.
The deck offers a console-like experience. The majority of PC games work, some may have issues, some may not be suited to the form factor. You can play console games on it but not out of the box.
I say this as someone who doesn't own a switch and uses their deck every night. I absolutely see the type of person who would buy a switch and the type of person who would buy a deck. They both have valid points for doing so and I'd never recommend the other device to them.
When it comes to playing Hades, Balatro or Brotato, I have had zero issues with the deck. It is literally a console experience there. Verified (green) games will just work and are indictive of a console experience. Playable games (yellow) dont represent a console experience. Small text, having to bring up a keyboard manually, launchers.. these things arent something you'd see on a console. Unverified games and emulation require the most tinkering and thats when you really get to experience it as a PC.
In its default state, playing only verified games, only in handheld mode, without external controllers - the deck is a fine machine and offers a console experience. Dock it to a TV, start using more controllers, fiddle with yellow games and that experience is gone. I absolutely appreciate I have the option to do so and not be locked out of it - thats why im a Deck person and not a Switch one.
My point is the deck cant replace a switch and the switch cant replace a deck. They complement each other fine.
Not to mention, a major reason why people buy Nintendo consoles is to play first-party Nintendo games. Sure, it's possible to emulate those titles on PC and probably the Deck, but a lot of people either don't know how or don't want to invest the time, money or effort to do so when they know the game will just work on the intended console.