The thing is that the porno producers will never be able to fight the piracy. If mainstream Hollywood movies have difficult time fighting piracy then porners do not stand a chance.

And the thing is that ripping DVDs is just plain fucking easy. You don't even have to have really good computer for it, and you dont even have to be smart to figure stuff out, because someone already figured it for you. There are hundreds of boards that specialize in this "hobbyist" backups and video tinkering.