For some highly-specific performance scenarios, Oracle still cannot be beat. I know far, far more businesses where a supported Postgresql is perfectly suitable. I know only one business where Oracle was a defensible technical choice.
Can you elaborate on this please? I do not think this statement is correct.
I've been maintaining trading backend databases for roughly a decade. What oracle does, db2, sql server, sybase can do. And postgresql, MySQL most probably too.
Most of the times the Oracle choice is dictated by a software editor whose devs are more familiar with Oracle and have an oracle first strategy.