AIUI (I don't have any of this hardware) SteamOS is really meant for the Steam Deck; while there's "basic support" for the ROG Ally, it's not their focus. Bazzite seems to be quite happy to support everything, and AIUI it's frighteningly close to SteamOS (the same customizations, etc.)
It's not "we have SteamOS at home" - it's more like RedHat vs CentOS
This is changing. Valve is actively working with hardware manufacturers to get SteamOS on a number of systems other than the Steam Deck. You can buy a Lenovo Legion Go S with SteamOS today[1], and Valve will be supporting SteamOS on the Asus ROG Ally in the future[2], whether Asus partners with them or not.
pavon|4 months ago
[1]https://www.lenovo.com/us/en/p/handheld/legion-go-s/len106g0...
[2]https://www.theverge.com/2024/8/13/24219469/valve-steamos-as...