There's simply a lack of need for it. There are lots of modules that you might be the only person to ever want or need.
in reply to Net::Bittorrent
Take for example one of my modules - XML::LibRSVG, and interface to the gnome librsvg API. Now this would be a very cool replacement for something like GD for building charts and graphs, along with a zillion other uses, if I developed it more thoroughly, but nobody ever asks about it, or posts bugs for it, so I can only presume there is very little interest in it.
But then there's things like DBD::SQLite. SQLite had been around for ages before I wrote this, but I was the first to write an interface to it. And it's now my most popular module by a long shot.
So don't give up hope - write the code and stick it on CPAN. It'll either get used or it won't, but either way you'll feel better for publishing it.