If you are still reading.... Richard Morrill digs into the natural decrease phenomenon in a detailed post at Newgeography.com: When Thanatos Beat Erps, Mapping Natural Population Decreases yesterday. Neat maps to look at as well since he is looking nation-wide. He explains this all more and better if you want to get into it.
So to be clear, I typically said lots of things to the journalists, and would rarely get to the natural population factoid until well into a conversation. But it always jumps out at reporters because it just is atypical or at least something they don't hear otherwise. I've learned well enough that journalists are not interested in hearing yet another person say what 10 others have ("Pittsburgh has been transformed"... yadda, yadda) and perk up when you teach them something even if its esoteric.
While Professor Morrill captures a lot of places where a similar trend is going on, a lot of those counties are rural areas. I try to be precise in my words and will usually say the Pittsburgh is the only large metro region with natural population decline going on right now. You will see from the map why I have to qualify that it stands out only among large metro areas. Even if you eliminate the truly rural counties there are a few other places that jump out and even within Pennsylvania the demographics of Scranton/Wilkes Barre jump out at you as being equally extreme.
But looking into the future. It's not like the natural population decline started immediately during the 80's exodus. Folks need to age out. In fact it would not be until the latter part of the 90's that natural population in the region would edge negative. Our natural population decline peaked early in this decade and has been declining (declining decline that is again) since. When and if natural population edges positive keeps changing in our forecasts. It might never get positive per se, but may not be as negative as it was a few years ago for a long time. Whereas there will be a bunch of places elsewhere in the US that will more and more look like we did over the last decade or two as they age out.