I worked for one company that used it. Everybody on the ground hated it but the costs of migrating away were enormous because every system they relied upon was tightly coupled to every other system. It would have been a multiyear project to get off it.

Their software wasn't just more expensive than using open source equivalents it was worse, too. It's just very, very sticky.

At the same time the sales team wine and dine key decision makers and try to strike the fear of god in to them so they don't rock the boat.

We heard you're planning to migrate away from Oracle. We understand, but unfortunately, that means we have to get rid of the 75% discount we gave you, so we'll make a decade of revenue in the two years it'll take you to get rid of us. Still planning to migrate away?

It’s a common ‘large enterprise’ dependency often due to some internal CRN/Accounting/Compliance software, so I suspect you are right.

People also marry the database when a significant amount of logic is in stored procedures.

Hard to do if it’s not present to use already?

> Every company I've worked for has avoided Oracle software of any kind.

Lucky you. Sadly, not all companies are new enough to be able to do that. Some embarked on Java when it was Sun, and Oracle when the only alternative would have been SQL Server (or DB2 on AIX, AS/400, or MVS).

A past company I worked for made SaaS and On-prem and we supported Oracle with the on-prem. The simple act of supporting and testing that option was enormous for our company, but the customers we had that needed it were highly lucrative.