Have you tried their original programming recently? At the turn of the century HBO and Showtime started producing really amazing original shows that easily rival any movie and have become the top tier of TV shows. I would venture to say that most people that get HBO nowadays do it for the original programming and not the movies.
These premiere shows had a much different feel than normal "big 3" network TV shows. They tend to be much more serial, with story arcs that go for whole seasons or even longer. They also tend to have much shorter seasons (generally around 8 to 12 episodes). This serial style really lends itself well to in-depth story telling and the shorter seasons means more attention is spent on each episode (since they don't have to constantly churn out new episodes all year).
An interesting technique that many of the shows use is to base themselves off a book series but make the entire 10 to 12 episode season cover a single book. Dexter, Game of Thrones, and True Blood all seems to do this with reasonable success. It allows them to get much more detailed than a 2 hour movie based on a book could possibly be.
These premiere shows had a much different feel than normal "big 3" network TV shows. They tend to be much more serial, with story arcs that go for whole seasons or even longer. They also tend to have much shorter seasons (generally around 8 to 12 episodes). This serial style really lends itself well to in-depth story telling and the shorter seasons means more attention is spent on each episode (since they don't have to constantly churn out new episodes all year).
An interesting technique that many of the shows use is to base themselves off a book series but make the entire 10 to 12 episode season cover a single book. Dexter, Game of Thrones, and True Blood all seems to do this with reasonable success. It allows them to get much more detailed than a 2 hour movie based on a book could possibly be.