I agree, totally. Of course, you also have the bitches like this who go out of their way to cultivate one "weird" interest--whether it's genuinely weird or not (usually not--even their weird stuff tends to be really generic), and whether it genuinely interests them or not. Like, they'll decide to be really into Baltic death art or something (I just made that up), and spend a few days on the internet reading about it and downloading pictures to print & hang or occasionally post on their Instas to prove how deep and unusual they are, even though in their day-to-day life they don't think about or care about it at all. Or they'll claim to love Enrico Caruso, or spiders, or Victorian momento mori jewelry, or Captain Carrot comics from the 80s, and make a big deal about it to strangers because they think it makes them seem intellectual and fascinating. So they might be able to hold a conversation about one of those topics, but your point still stands: they are essentially shallow, and have nothing to add to adult discourse or the world in general.