I had the same thought and did put a finger on it. It's because we don't trust Amazon or any of the other media companies for "buying" content online - we don'

I had the same thought and did put a finger on it. It's because we don't trust Amazon or any of the other media companies for "buying" content online - we don't trust that the purchase is really permanent, eventually the company will go away or discontinue that service or lose the rights to that content or whatever. Since we don't trust them for buying, we don't trust them for renting either, even if we'd expect the rental transaction to be over in a day or two.