Why do we have tenfold karma for front-page posts, anyway, as opposed to say threefold?

ETA: yes, front-page posts draw in newbies in a way that is probably undercounted with onefold karma, but it's my impression that the collection of LW's comments is a lot better than the collection of LW's top-level posts (at least post-Eliezer), and so maybe we should just be directing potential new users immediately to the (good) comments instead, somehow. It seems to me that by having length as a de facto requirement for top-level posts, we encourage posts that take a long time to make their point and that go off on long chains of independent steps that have mistakes in them that could be corrected if they were presented in smaller chunks.