They served JFKFRA briefly, VERY briefly, in the 1990s then around 2001 I think. Some people are still complaining that it is gone. Time to move on. And yes - if PHLFRA had been so successful year round, they would have kept it year round.

The point is, for the most part, flights to German business centers such as FRA and MUC are HIGHLY dependent on the German corporate point of sale. AA cannot touch it - they all go to LH and UA. There's a reason UA does well in FRA and MUC and the others have far less success. It's their relationship with Lufthansa. Germans are very brand loyal, and that's it.