Well, it is called Hacker News, not Hacker Show. Looking at the Show page (which I rarely do), most of even the top page has hardly any comments. People come here for news, to discuss things...For me, some of the best things are on AskHN. Mostly when I've asked questions, I get little or no response. They're things
I would comment on if I saw them asked, I eagerly await answers, but usually..not much response. (I didn't post "Is Hacker News broken?" asking why HN ignored my fascinating questions, saying how HN doesn't know quality etc. That would've been weird, don't you think.)
People are busy with their own stuff. News, I guess, being generally informed, comes under "one's own stuff"; checking out other's peoples' stuff, especially the new and untested, is something else. Probably mostly not worth bothering about.
Why assume the voting would be accurately proportional to the quality of the submission? Although you seem to be comparing News clicks with Show clicks - apples with oranges. It's hard to put oneself in the shoes of an imagined HN reader, what would make them want to click through to something. Probably it's good that people can't guess - if it was the total 'echo chamber' it's accused of being, people would share more similar taste, I guess.