That’s one reason corporations make new UIs, yes, but the other is users demanding them for the sake of novelty. Reddit (but not only) is filled with people with no design sense complaining about how something which works (because it was relentlessly iterated on) looks “stale” and “old”. They’re the same users who jump from app to app willy nilly just chasing novelty. Any turd, if hyped enough, is ailed as “the future”, “modern”, “innovative”, which is repeated drivel from what the corporations tell you when they introduce their next thing.