New fair movie downloads

I propose that the MPAA make the first half of all movies available for download.
If it's enjoyable then you pay to see the second half, if not then you don't bother. There have been a few films I've watched all the way through just because I'd paid for them, if they had just been on TV I would have changed channels.
I think they'd get more sales that way as loads of people would download all the latest movies and watch the first half, then want to see the second half. It's a bit like shareware for software where you can try it for a bit and if you like it, pay to continue using it.
By increasing the volume of sales significantly they could trim their prices to a point where piracy would become pointless.
Anytime a product is expensive to obtain there will always be people trying to sell cheap versions because there is a margin for profit in it, the only way to avoid this is to remove the margin or make it so small it's not worth it.