The way posts work on HN is a bit puzzling and not immediately obvious - I'll post something and then refresh the front page and won't even see it. The Reddit model seems simpler - I post something and it appears.
I think you're correct. A Show HN that goes nowhere fast will disappear and be seen by virtually no one. An equivalent in r/startups or similar will still be seen by a few people even if it doesn't attract comments or upvotes.
A lot of interesting information from the author over there.
META: Interesting to note how much cool stuff is turning up on reddit first before it appears here... I feel like it used to be the other way around.