There are three kinds of people who leave their hometowns as adults. There are those seeking opportunity, taking the best job wherever it lands them. There are those that seem to inspire so many Hollywood stories: young people convinced their dreams are too big for the towns where they were born and determined to "get out." And there are those who leave by force.
I'll start with an academic perspective. Push and pull factors are two forces of migration. The term "refugee" refers to a disaster (natural or unnatural) which pushes people out of their homes. When I criticize brain drain initiatives, I'm thinking about the pull of a global city. Most of my family would probably still live in Erie if economic forces hadn't pushed almost all of them to places such as Charlotte. However, "cool cities" aren't designed to deal with this problem and the lure of greener grass doesn't engender a loyal diaspora. We're spending a lot of time and money chasing people who don't want to stay.
I could frame this dichotomy as Mark Cuban (Pull) versus Mike DeCourcy (Push). Technically, both are members of the Burgh Diaspora. But people like DeCourcy (economic refugees) are the ones to network or help boomerang back home. Simple out-migration does not a diaspora make.
I wasn't sure if I had anything useful or interesting to say about DeCourcy's piece. As I've meandered my way through this post, I think I have a better understanding of what makes the Burgh Diaspora so special and why Steeler Nation appears to be so prolific. The unique demographics tell the story. An entire generation was lost, an entire generation of refugees.