This is one of the reasons I get quite nervous when people start talking about these private-implementation, "cloud native" database services (Aurora, Redshift,

This is one of the reasons I get quite nervous when people start talking about these private-implementation, "cloud native" database services (Aurora, Redshift, Spanner...). As wonderful as they sound (and possibly are), not only are you binding yourself to a single vendor by adopting these, but there is nothing to keep the pricing of these services connected to reality. Whereas as long as you e.g. "keep it postgres", you're able to experiment (at fairly low effort) with different database setups and find what is more efficient or cost effective for you. If Cloud Provider X's pricing model starts to deviate from what people are able to achieve with some custom database setup, people will start flocking to that - and, in fact, Cloud provider X would probably find themselves competing with an easy to use "managed database" service that does just that on their own Cloud Marketplace. Not that this isn't an extremely interesting project as long as it's possible to wrestle the concept free from Amazon's infrastructure.