Many companies have nobody who can do that work competently, and would rather focus on development. If you've ever had a random IT person "set up a database server", only to discover it barely has any memory or CPU allocated, it's configured with the slowest storage options possible, and it has no backups or monitoring, well... that's what you're paying for.
In actuality I think the number of people I have worked with in ~20 years that I would trust to set up a production database to the same level to which I trust RDS… is maybe like 2 people. Those skills are RARE and hilariously underestimated. “Just run a Postgres VM” is so far from the mark I can’t even explain.
