They hire at higher pay because they want people that can/are willing to do the job of multiple people

I guess that companies which get bought might be a bit "overstaffed" from the startup phase or because planned further development. If one removes this staff, you need less people to minimally maintain a running app. But itcs just a guess, you'll loose knowhow too, when drastically reducing your staff.

Being a part of that skeleton crew likely involves different skills to building the product in the first place.