You have a point, to a certain extent. People who already have a high reputation seem able to post junk and still get it upvoted. Whereas those with low reputation can post quality and it'll be ignored. I think the secret is to study the system closely, work it, and gradually build your reputation up. Then, once you have your rep, you can post your quality content and it will continue to do well. In summary, it's a matter of pulling yourself up with your own bootstraps. It's not easy, but then, it's not necessarily meant to be.