Oops- my mistake about the ERJ/CRJ Mesa ops.
The 1968 bond covenants were logical at the time, since Ft. Worth had previously built a thoroughly modern (for the times) airport called Amon Carter Field, later renamed Greater Southwest Int'l, which shriveled up and died. Its last remains can be seen at the south end of DFW, as remains of runway which used to cross SH 183 (I assume that's still there, isn't it?).
So the fear of DFW's failure was real, AT THE TIME. But at that time, AA's DFW/DAL operation wasn't big enough to warrant its own terminal; Braniff International was the only carrier which had enough traffic to command its own terminal.
AA now stomps around, consuming 2.5 terminals and wanting more, and the DFW Airport Board is administering a massive expansion, including a new International terminal.
AA just doesn't want WN to be able to compete on long haul flights, and bring real price pressure.
As for Legend, AA contends that the new airline will be "cherry-picking" its cream- its full-fare-paying pax (coach and first-class).
Of course, Legend will never have enough capacity to genuinely threaten AA. AA just likes to keep fares high and service mediocre.
...three miles from BRONS, clear for the ILS one five approach...