Yeah, but AFAIK that means people buying companies, leaving them with a skeleton crew and milking the remaining users as long as possible.

How does that fit with expensive hiring sprees? If anything I’d expect them to be continuously shedding absorbed employees.

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

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.