[Demiurge]

I made another comment already how it's trivial to start a web project with SQLite and migrate to a 'real' database, or continue to use it interchangeably for local development.

But I also just realized, there is a whole ecosystem of ORM based apps that can run on any of the supported databases. If you ever used an MVC framework and re-used apps, you have "switched databases" without even knowing, depending on what the original developers used.