nobody gives a fuck
Nice language and I doubt you speak for everyone.
The nickname was given to them because they were on TV so often, not because of their success.
And also, this.
Dallas the TV show was on a lot and broadcast nationally, but most Cowboy regular season games were only broadcast in their local market and that of the opposing team. Of course, because the Cowboys made the Playoffs in 18 out of 20 years, that led to the Cowboys being seen nearly every year in the Playoffs nationwide since playoff games are broadcast nationally. But that is simply a side affect of the teams success and no different than what the Patriots have done the past 16 years.