> But maybe it was not used enough?

Likely not used enough, yet. It would be premature to drop support this quick, as Google seems to just now move Android in the direction (DEX by Samsung is the same thing, but it's Samsung specific).

At the same time, only last year I saw a device in which I'd "dock" my phone (the Nexdock looked reasonably priced) and having both a phone and the steam deck with desktop mode would make such a device more useful.

I know you're talking strictly from the perspective of display glasses, but convergence is the main category under which I'd classify this feature.