I feel like Wikipedia is different because it actively harms the platform when people put up non-notable content, since it reduces the signal to noise and turns

I feel like Wikipedia is different because it actively harms the platform when people put up non-notable content, since it reduces the signal to noise and turns the platform into a way to launder legitimacy/importance. For example your local dentist should probably not have a wikipedia article, and you don't want there to be an arms race of every local dentist trying to get a wikipedia article so that they seem important. The other issue is that many novice contributors write with an improper voice and don't cite their sources - which again lowers the quality of the platform. Stack Overflow is different, as long as a question is on-topic and not a very close repeat I think there is no great reason to close it.