I agree and disagree with various points in your post.
I'm sure 2ch didn't have something to "make it famous" at first. It was famous before Densha Otoko. And I'm sure the choice of 2ch-style software wasn't made to ensure some sort of "automatic popularity."
However, I agree that 4-ch will probably never be quite as popular as Japan. Western culture is so rooted in the idea of identity that the anonymous BBS concept will never catch on here, at least not to the extent that it has in Japan. I believe that it can become more popular, though. It will just take time and dedication by the users.