Dallas is back and why are they cancelling these TV shows?

Are our tastes so different from the majority of TV watchers? I can't figure this out. It seems the majority of shows we are watching have been cancelled. Here is a list of additional shows we won't see in the next lineup of shows:

Alcatraz
Awake  (I'm the only one in the family who liked it).
Missing (What a great show. Plenty of action and suspense. And no stupid humorous dialog!)
Ringer (That one probably ran its course. I can't see how they could continue. It was a good show. Good action and suspense.)
The Firm. (They moved that show to Saturday, which is a death sentence. I don't see why. I loved the show).
Unforgettable. (This one was interesting. I liked Poppy Montgomery as the cop with a photographic memory. She's a nice-looking woman and a good actress. Perhaps I liked her because of her red hair. But...the show was cancelled).

This may prove my theory correct: Viewers don't like shows where the main character is a woman. Unforgettable, Ringer, and Missing had a woman as the heroine. Sod did 'Chicago Code' and 'Prime Suspect' (also cancelled some time ago). I hope my assumption is wrong.

I am happy to see these shows coming back, but they are not available on regular television:

Hell on Wheels  (A cowboy show about the railroad and revenge)
Game of Thrones  (Fantasy)  Best show ever for a long time.
The Walking Dead  (Science Fiction)
Falling Skies    (Science Fiction)

I hope 'The Borgias' will return. That is a great show. I'm surprised the Church hasn't boycotted that one yet.

Some of the new shows I'm interested in:

Continuum  (Time Travel)
Revolution  (Science Fiction. Apparently, it is about when electricity stops working).
Dallas (Yes! Dallas is back. The New Generation. We'll see.)