To a very close approximation, Postgres does do everything.
And on the very uncommon cases that you need really something that Postgres doesn't do, Oracle, MS SQL, DB2, and co do not provide enough of a difference, and what you actually need is an specialized DBMS.
And on the very uncommon cases that you need really something that Postgres doesn't do, Oracle, MS SQL, DB2, and co do not provide enough of a difference, and what you actually need is an specialized DBMS.