As much as I love Valve I think it'd be weird for a 3rd party handheld to boot directly into the Steam UI. I get that there aren't any viable alternatives atm, so I guess this is where we are. Wouldn't hurt with a more store-neutral solution, in the end.
If I am not mistaken, you /can/ have that be a thing, as I am fairly sure the actual SteamOS is open source and Valve would /probably?/ allow that to come stock on a potential alternate handheld...
But kind of their whole thing is it is optimized for the hardware set up they are using.
So... you could theoretically have an or multiple competing Not Valve but Yes SteamOS Decks, but from the standpoint of the economics of building a market viable gaming machine, Valve would still probably have a serious edge in that market for a while.
Almost like Valve actually understands the entire tech industry better than nearly any other tech company or something.
Honestly, I disagree with Heroic not being good enough, I think it's the only other launcher on Linux that is. It's very polished and everything has worked out of the box for me. The problem is simply that it's unofficial, no company would ship it on a gaming device.
It would be better if I could boot up and chose my launcher just like I choose Netflix, HBO, or Hulu from my Roku home screen. Of course, that could be accomplished with a custom front end / explorer in Windows, but since MS is pushing more into the OSX "we own the experience" with tons overhead and reduced customizable UI, and none of the other launchers support Linux, it's pretty much just a pipe dream.