> Some examples of this would be Oracle Identity Manager (which is absolutely awful but is still actually the only IdM solution really capable of scaling with massive enterprise companies)

The "massive enterprise company" I work for doesn't use Oracle IdM ...

It was used at the previous company I worked for, but it had endless problems and I think it was only bought as part of a very badly-run "buy an expensive 'enterprise content management platform and then not use it properly' initiative".

It's main feature seemed to be to import identities from LDAP servers into an Oracle database fronted by a very poorly performing non-compliant LDAP server (or, you could say, selling Oracle Database licenses).