The movie industry made the same crusade against VHS when it was released. They opposed it, claimed the practice will shut them down forever and destroy the market putting them out of business. Did it? Of course not. They eventually embraced it as a distribution medium and they were bale to even increase sales.
Digital distribution is no different. Once they embrace it, like the music industry has, people will be willing and able to buy it that way. It is much more convenient and easy to download than go out and buy. It should be cheaper as well, considering there is no physical media to produce. The movie industry has thus far not embraced it though so people will continue to obtain the movies they want in the new format they want regardless if they have to pay or not.
The movie industry has so far almost completely shunned the idea of digital distribution. Even the ones they've done, they are still doing wrong. They impose insane DRM, and expiration. Not to mention do not discount for the lack of producing physical media. It screws over the legitimate consumer so much, I can't see a reason to recommend buying it legit over pirating to be completely honest.