The really funny thing...
...is that, back in the 1980s when Oracle was a relatively small new company struggling to expand and make a name for itself, it competed against the likes of IBM and DEC by stressing its portability.
I remember DEC sales support people complaining how hard it was to persuade customers to buy Rdb when Oracle salesmen kept arguing, "What if you decide to move off VAX/VMS? Oracle runs on 43 (or whatever) platforms".
We DECcies all thought the joke about how Oracle runs best on a slide projector hilarious, but it didn't cut much ice with the punters. So zillions of customers bought Oracle, secure in the knowledge that they could easily switch OS and hardware whenever they wanted to.
And about 5 percent of them ever did.