It looks like Valve is stepping up their game! According to GPD, a mobile PC maker, Valve had reached out to them in March of this year to see if it would be possible to cooperate to get SteamOS supported and optimized for their newest upcoming product, the GPD Win Max 2. This was confirmed by GPD when, in the discussions of their Indiegogo page, they were asked by a backer about SteamOS support:
On top of that, they had responded again later confirming that they indeed feel this cooperation is a good idea and will take it:
While we haven't heard from Valve directly on this matter, this does seem to be in-line with their goals. Integrating SteamOS into more than just the Deck is pretty wonderful and it's great seeing Valve being willing to work with competitors to bring a fantastic OS for gaming over to other hardware.