They sell to people who buy. I realize that sounds like a tautology, but most of us don't buy software (at least, not often) and instead we primarily use software. People who primarily buy software care about and optimize for very different concerns than people who use software. There's a market built around selling a large product, which will be used by many different kinds of users, to just one specific kind of user, one who has been empowered to make organization-wide purchasing decisions. This is typically done by presenting to that kind of user a curated subset of the application's features, that subset usually being wholly disjoint from what most users will see. These software-buyers will be shown a pretty picture taped to an ugly mess, and since it meets their needs (to whatever extent they have needs for it), will decide to buy based on the pretty picture (and, sometimes, the accompanying sweet-talk lunches).
In another generation, the term "nobody got fired for buying IBM" was coined, and this is the kind of people it was talking about. Buying Oracle doesn't create controversy among their peer group.
Oracle's reputation is bad enough that buying it should result in a firing though. At least if it can be avoided. Remember all the unnecessary work they generated throughout the whole industry when they turned the Java license into a extortion trap for unsuspecting companies?
Yeah, I think their reputation isn't what it used to be. But it takes a long time for these things to percolate up from developers and lawyers to management, and another long time for them to spread from IT-focused businesses to other industries.
In another generation, the term "nobody got fired for buying IBM" was coined, and this is the kind of people it was talking about. Buying Oracle doesn't create controversy among their peer group.