That might have been true 10 years ago, but I think that the new arena fiasco and the recent surgings of the Pens will do wonders for the hometown fanbase. Nothing makes fans like winners or contenders, and the way the NHL playoffs are set up, it's much easier to get into the post-season than MLB. You might end up seeing a generation gap between people who remember the Pirates post-season and those who can't in the next few years (it's already been 15 years).
Unless the Pirates can somehow manage the success the Penguins should have the next decade or so there's no way the Pirates pass the Penguins.
A large portion of the Penguins fan base can't even remember the last time the Pirates were in the playoffs. I've been watching sports since 1993...the Pirates best record in that span was 79-83 a full decade ago. To say the least, the Pirates are not doing well with the younger crowd.
From someone who grew up in the south hills of Pittsburgh the Penguins are right there with the Steelers atop the sports heap in Pittsburgh. In other sections of town things are differently. The Pirates barely showed up on the radar. The Pirates impact within the city is still very much huge while the further you get away the less they show up. The Penguins seem to have the opposite impact as their fan base is more spread around the metro area.
I love baseball, but the Pirates godawful ownership is enough to keep them down my list.
No doubt Pittsburgh is a football town, this town lives and dies by the Steelers. It's that way in most cities, but Pittsburgh and the Steelers...well...yeah, it's legendary stuff. The Penguins will never compete with the Steelers in this city, but they have a pretty comfortable seat at #2 and the cushion will grow larger as the team continues to do well.
As for Philadelphia...it is a damn good hockey city. I go to school in central Pennsylvania smack dab between Pittsburgh and Philadelphia (though I'm one of seemingly 5 western Pennsylvanians going to school here, almost everyone is from Philly or New Jersey). I've seen maybe 1 Phillies hat, a dozen Eagles jerseys, 1 76ers jersey, and an insane amount of Flyers gear. That's just from my personal experience. Their attendance numbers in this terrible year do enough to show that it is a great hockey city. Hockey doesn't need to be #1 in the market for that city to still be a great home for that sport.