This is what i base my optimism on. From 2007, before they were even promised a team.
http://www.guardian.co.uk/football/2.../sport.comment
"They're fans of Philly's Major League Soccer team. But Philadelphia doesn't yet have an MLS team. Which is to say that, despite having scarves, songs, chants, replica shirts and flags, they're fans of a team that doesn't yet exist. It's almost as if - in the manner of the South Sea cargo cultists - they're trying to will a Philly team into existence. They even organise trips to New York Red Bulls games, just so they can boo them. How hardcore is that?"