It simply means that it doesn't matter how many articles you submit. If more people prefer other articles, with say more linkbait headlines, then yours will be buried. In short, simply submitting and voting is not a solution when more, many more people are voting other things up. More generic, shallower things.

And I flag a lot of articles, but very few of those get banned, same principle as with submitting. If a few people flag and a lot vote up, it stays. And "few" and "a lot" are relative terms here. They'll change with time.

I've seen narrow and deep focused discussions be replaced with wide and shallow discussions on many sites, but in rough order: Slashdot/Digg/Reddit/programming-reddit/science-reddit and I know I'm forgetting a few that came and went fast.