Re: good luck to them
Third-party software vendors have something to do with it, I'm afraid. Where I work we have a big "enterprise application suite" -- ERP stuff. It's a big nasty hodgepodge of PL/SQL, Pro*C, Pro*COBOL, Java, Forms, and other things that should be declared Not Safe For Work, very tightly integrated with the database and associated Oracle stack products. Unsurprisingly, the vendor certifies it compatible only with Oracle, and will not support its use with anything else -- I think they might even consider the use of another database product a violation of the contract or some other equally ludicrous claim. Fortunately, I'm not a DBA, nor do I want to be one.