>> ... mainstream database system ... > SQLite, with far more installations than Postgres, isn't a "mainstream database"? It's not a system, it's a monolith l

>> ... mainstream database system ... > SQLite, with far more installations than Postgres, isn't a "mainstream database"? It's not a system, it's a monolith library, which is why it is used wherever you want a local database with local storage. Postgres implementations are a client/server systems even if the connection is on localhost. It's also MVCC and has RLS and other requirements that do not necessarily apply to a local database like SQLite. It's not about the number of installations, it's the type of database.