Let’s just say hypothetically this was possible and that the laws of silicon were not a thing, and that there was market demand for it for some asinine reason. As well as every OS process scheduler was made to optionally work with this. How would this work?

Personally, I’d say there would be a smol lower clocked CPU on the board that would kick on and take over if you were to pull the big boy CPU out and swap it while the system is running.