What do you consider 'long term'?
I'd expect that for next 2 to 3 years DVD sales / rentals will be top, then most likely BR sales / rentals with DL last
After that it depends on how much average consumer has been pushed to HD TV & BR player vs something that can support downloads - remember number of homes with a console or something that can support downloads is pretty small compared to population with a DVD player.
I think its at least 10 to 12 years before downloads have a chance of being the dominant method for accessing film media. Sometime between then and when DVD starts to die in favour of BR (assuming it ever does) BR will have the majority advantage for quite a while.
Try to be reasonable... its easier than you think...







