Why do you need consultants to run a database cluster? And do you run AWS database clusters in production without expert knowledge? If you need consultants for self-hosted databases you'd probably also need consultants to properly set up AWS services.
Performance tuning, scaling, troubleshooting, etc. We had terabytes of active data (as opposed to warehoused data).
For example, if a disk fills or is fails, adding a disk to a mySQL setup without causing downtime is a pretty involved process but in RDS it is one config change in the admin. It does the same process just AWS put a huge amount of work into automating it.
We only brought in the consultant for an average of a day every other week but that adds up and we had to bring in 0 people after switching to RDS.
