Generally they buy companies which have been pumped with steroids (VC money). That have a good product with active customers but have unsustainable cash flow. They cut expenses, whether thats moving labor from silicon valley to europe, cloud hosting costs out of aws, etc.

Nothing new - happens in every other industry all the time. Usually companies get themselves into some sort of cult thinking so that only someone from outside can make the turnaround work. Nobody already working at a company and promoted from within is going to suggest moving the all the staff to Milan for example.