I don't think it's the "pure" opposite. Notably, it's extremely stable and even all of the quirks which aren't fixed for reasons of compatibility are documented in its built-in help.

I think almost all modern products focus exclusively on growth: acquiring new users. That means that it's OK to break existing behaviors if it makes something easier for a newcomer. Vim does not have this attitude, so a newcomer has a steep learning curve, but an old-timer doesn't have to worry about his platform changing from under him.