This is not true at all. The past 30 years have significantly dampened passion for the team, but it’s still surprisingly resilient despite Snyder doing everything he can to destroy it. The last decade especially has taken its toll, but if you went to a game as recently as 2012 the stadium was rocking.
3/4 of VA’s “blasphemous” population is not Cowboys fans, and I see less of them every year. I think the Cowboys’ mediocrity is taking a toll on their national fan base as well.
As far as the market goes, northern VA has a large population with some of the richest and most powerful counties in the nation. Add Maryland’s population to the north and a good team that’s fun to root for has a great opportunity to make a lot of money here.