Cloud computing is also like 100-200% surcharged, even after volume discounting. If you are not rapidly growing with uncertainty over resource requirements, you're going to get far better financial outcomes by taking your infra in-house. Example: Uber.

I'd slightly disagree with this - the real benefits from cloud are in the things you don't need to do. If you're just using the cloud as a normal datacentre (but in another location) you're not going to have a good time.

EG using a managed Database as opposed to rolling your own saves on patching, management etc...

If you're not rapidly growing and are paying millions in cloud compute, you should hire your own infra team and start managing your own database, so you can save millions of dollars.