DL gave up international F and is by far the most profitable US carrier with an international presence.
AA is giving up international F on most markets and is the second most profitable US carrier with an international presence. (BTW, you left DFW-HKG off your list of 77W flights.)
UA has the most extensive international F presence of the U.S. airlines on it pmUA planes and is the least profitable.
What could I possibly read into that?