I know the author of that one (my first online friend, from way back in 1999). He did a complete fic purge a few years back, but mysteriously decided that he was going to at least put up some of his old Teen Titans stuff again. His Zelda stuff is stuff that he's not proud of, so I assume that's why it didn't get reposted (even though it was bad on purpose).

I happen to learn a lot from writing the fanfic that I do, including (oddly enough) worldbuilding and OC-making, but considering that Bman canon is sparse, both of those things are kind of needed. But so what if people don't learn? People have different reasons for doing fanfic that may not include necessarily "getting better" at it, or for that matter with the intention of eventually becoming an original writer. Nearly every writer (original or not) starts out with the notion that the act of writing is, in and of itself, fun. "Getting better" at it comes with repeated instances of it, and it certainly improves the Fun Factor, but it may not be the writers' goal. They could just be doing it to blow off steam from a hard day at work. And of course it helps when authors follow established guidelines of basic writing in their fanfic and consequently produce something that's at least readable, but they're not obligated to do so for fandom at large.