I went through periods of losing faith too. But ultimately, HN = programmers, writers, and so on. What are the chances of any random programmer/writer being interesting? Much higher than the general population, for some definitions of interesting.

You get what you put in. It often doesn't feel like it, but in the long run it seems to work out that way.

You have to remember that HN is so massive now that it's hard to comprehend just how many people read the top comments. All the world is a stage, but HN particularly so. And personally, I think it's cool you can influence the situation by skill alone – a good top comment can salvage an otherwise hopeless situation.