Trust me, those hollywood execs aren't stupid. They are trying everything they can to keep their existing revenue streams going. Hulu proves that streaming can be done but it's very complex. It's easy for us to say 'just put everything online' but that involves millions, if not billions, of investment money to make that happen. Streaming video online is very, very, very expensive.
Depends how you define expensive. Netflix's CEO said it costs about five cents worth of bandwidth to stream a movie.
If the streaming side of it were expensive, sites like Megaupload never would have existed in the first place. They were primarily supported by ad revenue, which is about $3 for every 1000 views, or 3 cents per viewer.