To be fair, in this case, this isn't the studios. I believe the studios are actually looking into these things (though at a snail's pace, certainly, because they have to calm down all the people who freak out that any change in the business is bad for them, especially the exhibitors) and, thus, have told their representative -- the MPAA -- to go easy on it.
This is a private group, "The Copyright Group", which hires itself out to various low-level film companies that aren't MPAA-signatory, and they're the ones who are being this aggressive.
Here's a funny story, though - I met a guy who produced an ultra low budget movie I loved at a screening of his new movie, and was talking to him and his producer about this sort of distribution, and they told me that, right now, the bootleg that's going around the Internet is higher quality and with lower problems than the official one on their site that you pay for. It was, obviously, a huge complaint, because people were paying to download the movie and the download would be plagued with problems, so they were saying "Why can't we just do it like they do?"