The thing is, you need this equivalently for any cloud provider as well. People who know how to operate and run a cloud account effectively are not a dime a dozen, and given the migration going on now are actually in higher demand than some qualified datacenter operators.
Same goes for backups to S3 vs. setting up a SAN on the datacenter.
Managing AWS infrastructure isn't trivial, it's easy to forget what that instance does, if everything was provisioned with point and click. Cloudformation or terraform makes it doable. But technical debt is also something you can defer payment on :)
Additionally Aurora has robust zero downtime self recovery from a variety of error conditions including disk failures, and you can test that out by running a SQL query that simulates disk failures for example: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Auror...
This level of operational excellence is incredibly hard to build yourself either on premise or even in the cloud if you are only using VM's. Time and time again you see companies that thought they had backups but then discover the backups don't work right. It's not because these companies are stupid, its because it is hard to do right, and building and testing this requires a lot of engineer time. When you do take the time to hire the right people who can do it right you end up finding it is way more expensive to do it yourself than using a cloud managed service. AWS is able to offer the service much cheaper because the cost of development and maintenance, etc is spread across a huge number of customers.