Earlier quoted context omitted.
Is it though? This is a genuine question. My intuition is that the investment of time / stress / risk to become good at this is unlikely to have high ROI to either the person putting in that time or to the business paying them to do so. But maybe that's not right.
Managing the PostgreSQL databases is a medium to low complexity task as I see it. Take two equivalent machines, set up with streaming replication exactly as described in the documentation, add Bacula for backups to an off-site location for point-in-time recovery. We haven't felt the need to set up auto fail-over to the hot spare; that would take some extra effort (and is included with AWS equivalents?) but nothing I'…
With a managed solution, all of that is amortized into your monthly payment, and you're sharing the cost of it across all the customers of the provider of the managed offering.
Personally, I would rather focus on things that are in or at least closer to the core competency of our business, and hire out this kind of thing.