I doubt AA would take over for Qatar from DFW entirely, but possibly on one of the two daily departures. My guess (and hope) would be MCT or CMN.

Regarding PHL to “somewhere glitzy” I may stand corrected on DXB. Not sure what else it could be, and it does make sense in that it is enough of a standalone destination. This would enable many to travel there from the US with one stop and from nearly anywhere with no more than 2 stops all on AA metal.