I'd bet that the majority of what is watched on Netflix comes from a small percentage of power users. And that a large percentage of subscribers go weeks or months without even using it.
Netflix is better off with more very active users. Collecting $9/mo from non-users doesn't move the meter. If they have more subscribers and can demonstrate that those subscribers are very active, then they can get better rates on content...and better content will drive more subscribers. Having to add some additional hardware infrastructure to support more connections is small potatoes compared to the content side.