According to many reports, the Switch 2 sold 75% of the Steam Deck's lifetime sales in 1 day. That's not simply a matter of price. Valve would have to make many fundamental changes in order to make the Deck a real competitor to Nintendo.

Expecting the two to compete fiercely was a desire from the wackos who insisted that a match between a super heavyweight boxer and a lightweight could legitimately take place.

For sure, I don’t think it’s a failure by any means but “massively successful” is quite a stretch. There’s a large grey area between those two sides of the spectrum that it falls in.

People buy a Nintendo console for many reasons... But they never buy it for class leading graphics or performance.

The Steamdeck was about the best graphics hardware you could get in a handheld. (At the time.) - Whilst also establishing and building a software ecosytem. (Steam OS)
And that's the long term plan, to build an ecosystem that locks people in and feed them Steam games that Valve gets a 30% stake on.

But we need to remember that there has been zero advertising for the Steamdeck, it's 100% word of mouth. -There is also zero retail visibility.. Which is unlike the Xbox, Playstation and Switch which is in thousands of retail stores around the globe.
And that is purposeful, if you are a PC gamer, you know about the Steamdeck. - But the Steamdeck isn't meant to sell 100~ million consoles, it was designed as a platform to develop SteamOS which will get adopted by PC manufacturers who will do the hard work with the hardware.

I don't expect PC handhelds to erode Nintendo -at all- PC gamers are PC gamers, usually we can afford to feed our habit so have no issue buying multiple devices, so with that... We will either buy a Switch 2 or we don't... And the existence of PC handhelds won't change that.

It's massively successful in the sense it was a great platform to launch SteamOS which will then be taken by hardware manufacturers and impregnate hundreds of new gaming devices that will deliver Steam games in the future that valve gets a 30% profit cut on.

Imagine a hacked Switch 2 running SteamOS in the future? The possibility is there.

Valves strength has always been software, not hardware... I think people forget that.

Haha, no. Switch 2 week 1 has likely outsold the Steam Deck lifetime.

"Over 3.5 million units sold in the first four days - The fastest selling system at launch in video game history."

Lol, what pricing disaster?!? XD

Yup, this was supposed to be Nintendo's PS3/Xbox One moment despite nothing Nintendo has done matching such a description.

Switch 2 not being sold out everywhere is now a meaningless observation, because the announced sales confirm that Switch 2 had much more initial stock available than any other video game system ever. Switch 1 shipments for the entirety of March 2017 were 2.74m.

Funny anecdote: Today I met an acquaintance who I wouldn't have thought of as being interested in buying a Switch 2 at launch, and he said he couldn't get one so far, but at least has bought controllers. He also mentioned that one of his friends already got a Switch 2, another guy I wouldn't have thought of as an early adopter. But maybe that's important here: All the whining on the internet came from hardcore gamers who are on a tight budget. Normal people have money.

This.

Nintendo knew there was a big demand for Switch 2 both based on their own actions and other factors. With 3DS selling well below DS and Wii U failing, it would've been rash for Nintendo to manufacture and ship millions and millions of Switch units right away. 

At least right now, Nintendo's confidence seems to be paying off right now. And it likely will going forward. 

People would still pay $500-$600 for an unbundled Switch 2 even if it hurts sales to some extent. 

Phew...