I don’t believe the sky is falling, nor was it my intention to imply as much.
While I don’t have a similar size of data, I have now moderated (or admin’d) 4 different Discourse sites, all with very different purposes (gaming, knowledge-base, internal site, ticket system). For most users (likely ~90%) I never heard anything about notifications levels, positive, neutral, or negative. My guess, (this would be an interesting Data Explorer query), is that those users never touched notification levels, as the defaults were good. (Side note, that speaks volumes to the defaults the team has chosen). Where the issue lies in when users start asking about notification levels, and request enough detail that we start to deal with the overlap of settings and such. This back and forth is a good example of the types of discussions I’ve had on my different sites, as well as offline when leading a training session.