Chris Anderson's The Long Tail describes the very thing you enjoy about Netflix. In fact, company data given to Anderson revealed that an entire 25% of the company's sales are generated from non-blockbuster titles -- the "back catalog".
Its probably more, due to the convenience effect. Its the same reason companies cluster restaurants: people go to the cluster knowing it will have the best selection. In the same way, people go to Netflix knowing they'll have the best selection, and sometimes they end up choosing a blockbuster title.
