Postgres also has a number of commercial derivatives, so you get the advantage of starting small (open source) and moving to a more optimized derivative when it

Postgres also has a number of commercial derivatives, so you get the advantage of starting small (open source) and moving to a more optimized derivative when it becomes necessary. Aster and Greenplum perform exceptionally for what they do. If SQL Server were better that's exactly what companies would use. Commercial engines are definitely more advanced. But some Postgres derivatives can absolutely out perform enterprise platforms in some uses-cases, and vice-versa.