Good point about making money. But we're using a service that lets people discover stuff on thousands of small sites in the way you describe. (Before this site existed, I used Slashdot to discover stuff, and before that Usenet newsgroups.)
We're here today, but we'll be gone tomorrow(-ish). Before HN I was on Reddit, before that Digg, before that Slashdot, and so on. Being in any particular place at any particular time is no guarantee we'll be there going forward because the social networking anacyclosis is undefeated.