Putting cellphones on big standalone monitors might work. But in that case, we’ll probably also need to attach a pointing device and some way of entering text, so from a UI point of view, we’ve got a desktop.

Cellphones definitely have sufficient processing power for lots of typical office workloads nowadays… but using them in this way doesn’t seem to have caught on.

I dunno, eventually this sort of discussion ends up at “why didn’t DeX take over the world,” a question for which I have no good answers, since, like everyone else, I never tried it out.