This is the heart of the issue, isn't it? Aereo can provide this service for so cheap because it's using someone else's content for free. They don't themselves create or provide anything users actually want to buy--they just distribute the work of other people, and do so without compensating the people who created the products that are actually in demand.
I don't really buy Aereo's claim that somehow this implicates cloud computing. Lawyers and technologists can argue about how Aereo's array of individual antennas interacts with the public performance aspects of the Copyright Act, but I think ordinary users wouldn't view Aereo as a "cloud computing service" akin to Drop Box, but simply a website where they can stream TV shows for very cheap (ala Hulu).