Netflix's number one problem is that the companies who own the content don't (for the most part) want them to succeed. They take too much power away from the content owners. Netflix would happily offer EVERYTHING via streaming. The content owners would rather Netflix weren't allowed to send disks out by mail, but there's that pesky problem that it doesn't violate copyright law.

Maybe Congress will create compulsory licensing for streaming like the compulsory licensing that makes radio possible. Or maybe they will allow content owners to license DVDs instead of selling them and Netflix will cease to exist.

I have dealt with cable companies and I have dealt with Netflix, and I know which side I am on.