There is another way the industry could use fan edits to their advantage - as a source for hiring potential new editors for future projects. In effect, any fan-made artwork - edits, song parodies, DVD case covers, fan films, CG renderings, and so on - display that person's talents to the industry. Why isn't the industry then smart enough to look at this pool of talent and make job offers to them? Just because a film or TV show was produced by people who were paid to do it doesn't mean it was done well. There's always room for improvement to some degree.
The existence of a fan edit also doesn't eliminate the existence of the original. They're not being distributed in stores, selling better than the studio version. The size of the audience for fan edits is infinitesimally miniscule compared to the general population that buys and rents DVDs in the first place, so it's not like they're a threat from the perspective of confusing the public as to which is which.
The industry has such a selfish, controlling, dictatorial attitude that they manage to piss off the very same people they depend on to buy their wares in the first place. Coming down on any fan-based work that attempts to improve or build on the original in some way is like doing extra credit for homework and getting detention for your efforts.