Yes. Once the true next gen games with heavy compute and bandwidth start rolling out I'm guessing the Steam Deck is going to be a 720p machine at best. Maybe that's good enough at 7". It'll be interesting to see. If not, S mobile is likely 4 years out, but I'm wondering if MS bothers.
I still think MS only cares about GP subscriptions. The only reason to go mobile is to please GP subscribers, but it's not mainstream enough for that yet. If 25 mil grows to 50 mil four years from now, there might be enough people that really want GP on a mobile platform. Definitely at 100 mil they could make it work.