Show HN shouldn't be a platform for advertising startups anyway. Too many submitters try to "show" landing pages which are nothing more than subscription forms, or services which have no published source code and require signing up to even see what it is and how it works, to get viral and get traction.
Being a place for people to show off their code and their (possibly incomplete, and not necessarily for profit) projects is what makes Show HN unique, on a forum otherwise biased towards startups and SV culture.
Of course, I recognize my personal opinion on the matter is not really relevant, but I don't think low volume is necessarily a bad thing.