Fair! Although I've never worked with a shop that was not-Oracle and migrating to Oracle. Sadly, there's the long tail of places with existing, business critical Oracle use.
Anyone that wants top tier RDMS, it nice graphical debuggers for stored procedures, integration of Java and .NET into the database, distributed transactions, raw file system accesses, web services on the DB layer, among several other features, besides Oracle, there is only MS SQL Server and the RDMS owned by IBM like DB 2 and Informix.
MySQL and Postgres are kind of nice, but not really the same league at tooling level.
This is completely in line with the premise above.
If the database is primarily a data store, unseen by the end user, then Postgress, Firebird etc are fine. If however the database is an active part of the development stack, being used by lots of "users", writing new code etc, then commercial offerings with better tooling win.
I think Cisco still uses proprietary software too.