I generally like the OP's posts, but I really don't buy their argument. If anything, the nintendo switch winning the last generation is a great example of how hardware isn't always that important, the game library essentially is what makes a console win, and in as much as the hardware enables the breadth of the library, that's all that matters.
Like the steam deck, I don't know who other than power users who will buy it. I love the openness they will bring to the market, but that doesn't mean they will win.
I would totally buy it, if it's not silly expensive. I am not a power gamer or whatever, at all.
I absolutely do not want gaming mingled with my primary PC usage, work and stuff. For reasons of OS choice, data integrity, security and distraction management/work-play-separation. Can't over-emphasize the importance of this. But to me there is no question PC gaming is superior. However, I can't justify building a full-blown "gaming PC" just for gaming.
Some years ago, I got a PS4 Pro just to satisfy my occasional gaming urge and I love the console form factor, no tweaking and press power to play ergonomics. I wish I could install some mods for old games, tho, and the PS4 library is super limited compared to Steam. I also feel sad, the PS lock-down means unnecessary hardware obsolescence. And I hate Sony's rent seeking for online services and would never buy PS Plus.
I know quite a few people in my social sphere who are exactly in the same spot I am, who would love exactly what's shown with the Steam thingy. It will all depend on the price.
Like the steam deck, I don't know who other than power users who will buy it. I love the openness they will bring to the market, but that doesn't mean they will win.