Who’s growing and who’s shrinking and what it means.

However, we do have 1 non-stop daily from PHL to SAT. I may be wrong, but it seems to me that more and more of the U.S. to Europe service is moving to PHL from JFK or, if new, just being assigned to PHL. Knowing some hardcore New Yorkers as I do, they will NOT bother with traveling to PHL for the privilege of flying AA to Western Europe destinations unless it's the only non-stop to a particular destination (a very remote possibility).
 
AA doesn't expect hardcore New Yorkers to go to PHL. They've determined that they'll make more money running some flights from PHL due to the inbound connection options and no slot restrictions. It's all about maximizing revenue. If you want to go to points in Europe that AA doesn't serve from NYC nonstop, they'll happily route you through London or Madrid.