Obviously just so many reasons why this won't happen. Or would happen on iPad first. But dare we dream?
There are some practical issues with having to make sure you have the screen and keyboard access (in practice the all-in-one of a laptop is pretty handy - though I guess you could still have this form factor in a much lighter shell minus the compute) but for a lot of cases like home <-> office this would be the dream, just carry your computer in your pocket.
The RAM shortage is only starting to hit but I think this could potentially start to be more appealing if it lasts too long and gets too bad.
That'd be the dream