The bottom line is this...

Because catching someone (your paying) fucking on film is easy, the biggest retards get into the business. For the most part, porn 'companies' can barely figure out how to edit raw footage, let alone keep their works from getting ripped off in ten seconds.

Besides, when every porn producer is using fifty third-party VOD providers/distributors, it makes it pretty easy for some DVD copies to get into the 'wrong' hands - primarily because the third-parties don't give a fuck if the guy ripping and encoding the DVDs is saving copies on disk to take home for his buddies.