Once you scale you'll need DBAs anyway to do things AWS won't do for you,or developers with the same skills, like figuring out why your developers are writing queries that kills the production database because they didn't test with data sufficiently similar etc.. I used to manage about 100 Postgres instances alongside ca ~1000 VMs total spread across colocated servers and managed hosting in several countries. The time I spent spent on the type of DBA tasks that e.g. AWS RDS automates away from you was measured in minutes per month after I'd spent a few days automating backups and log shipping and failover.

I kept being asked to price out a migration to AWS, and we kept coming up with 2x-3x the cost. Part of the reason was that we could pick and choose servers that fit our workload in a way we couldn't with AWS, and partly the absolutely insane bandwidth prices AWS offered.

I use AWS. I like AWS for the convenience. But it's a luxury that is ok when you're either small or really high margin, and you're paying massively over the odds for that luxury.

The reason these services get away with being so expensive is that people massively overestimate the complexity and don't bother actually getting quotes from people or companies to manage these services for them. When I was doing consulting my biggest challenge in offering up alternatives to AWS was that people were so convinced AWS was cheap that even when presenting them with hard data they often didn't believe it. For me it was a mixed bag - I tended to make more money off the clients who stayed on AWS as they usually needed more help to keep an AWS setup running than those I migrated to managed hosting setups, despite paying more for the hosting too.