Any Linux distro can have MySQL or Postgres installed in less than five minutes and works out of the box
Even a single core VPS can handle lots of queries per second (assuming the tables are indexed properly and the queries aren't trash)
There are mature open source backup solutions which don't require DB downtime (also available in most package managers)
It's trivial to tune a DB using .conf files (there are even scripts that autotune for you!!!)
Your VPS provider will allow you to configure encryption at rest, firewall rules, and whole disk snapshots as well
And neither MySQL or Postgres ever seem to go down, they're super reliable and stable
Plus you have very stable costs each month
It depends:
- do you want multi region presence
- do you want snapshot backups
- do you want automated replication
- do you want transparent failover
- do you want load balancing of queries
- do you want online schema migrations with millisecond lock time
- do you want easy reverts in time
- do you want minor versions automatically managed
- do you want the auth integrated with a different existing system
- do you want...
There's a lot that hosted services with extra features can give you. You can do everything on the list yourself of course, but it will take time and unless you already have experience, every point can introduce some failure you're not aware of.
I totally agree with that, but in my experience 99% of "application developers" don't need all these features. Of those you listed, I only see "backups" as a requirement. Everything else is just - what I said - features for when your application is successful and you want something streamlined.