1. Our customers run our software on their own machines for security and data-control reasons. As soon as something's running on someone else's hardware, the data is out of your control. Unless you're going to accept the (often massive) cost of homomorphic encryption, AND have a workload amenable to that, it's a simple fact.

2. Everything we do in house is small enough that the costs of running it on our own machines is far less than the costs of working out how to manage it on a cloud service AND deal with the possibility of that cloud service being unavailable. Simply running a program on a hosted or local server is far far simpler than anything I've seen in the cloud domain, and can easily achieve three nines with next to no effort.

Most things which 'really need' cloud hosting seem to be irrelevant bullshit like Facebook (who run their own infrastructure) or vendor-run workflows layered over distributed systems which don't really need a vendor to function (like GitHub/Git or GMail/email).

I'm trying to think of a counterexample which I'd actually miss if it were to collapse, but failing.