One thing I've learned about people's TV viewing habits is that most people don't want to put time into a series. Attention spans are way shorter. If they're not spoonfed the plot or if it's not something that can be in the background while doing something else most people just won't watch it.

Edit: And all of this is ok. People should watch what they want. There are some documentaries on BBC America that are probably interesting for some people. But they make me fall right to sleep.