Disagree. NFL may be the most popular nationally, but here, in terms of popularity, I'm not sure about the Eagles being the runaway favorite. They're the favorite year round on sports talk radio here for sure but the reality is far different.
Years ago, when I was growing up, Eagles games were blacked out a lot because they could never sell out the Vet. Most of the time, for them to sell out the Vet, it depended on the opponent. So Eagles/Dallas was always on tv but you never saw an Eagles/Cardinals game.
Flyers, on the other hand, always sold out even when they were one of the worst teams in the league. Their support has never once wavered.
On top of that, there are many other fans of other teams who were born and raised here. We have a ton of Cowboys fans, there's some New England fans now, there's even quite a few Raiders fans.
Now, contrast that with people who were born and raised in Philadelphia that follow all the major sports, and you'd be EXTREMELY hard pressed to find anyone who was born and raised here that is anything other than a Flyers fan.
It doesn't stop there, either. The basketball history in this town has few peers nationally. Few can match it.
Philly is also a fighting town so boxing also holds a special place here as well.
Phillies and baseball history go further back than most towns in this country have been in existence.
Philly is basically an everything town. Probably the only town in the country that can make that claim.