WWE, until recently, was the only outlet to watch pro wrestling on TV every week.
To clarify, comparing wrestling to other TV programs is a bit of apples and oranges. The Simpsons started to suck, but it wasn't the only comedy show on TV. People had other shows to watch that provided simliar entertainment.
When WWF was shitty, we had WCW and vice versa. Now its WWE or TNA in a poor timeslot. WWE is more accessible to people who want to watch wrestling.