AA used to have a hub in STL; due to its "southern"
location less prone to ice/snow issues than ORD.
IF they were to abandon ORD, I'd vote for STL. Why not bring back STL to lessen ORDs heavy flt load???
Not enough of a business base in St. Louis with just a smattering of big corporate seats and it doesn't stand out as a particularly popular international/vacation destination. With AA closing the pilot base in STL and nothing regularly larger from AA than a 737 passing through, it probably has not made business since for some time, even before the current management team. Even Delta doesn't operate a Sky Club at STL (while American did at least remodel theirs following a tornado instead of just closing it under the auspices of an undetermined re-open date).
About twenty years ago it was possible to hop on a TWA wide-body to LGW or CDG from STL and at one point FRA was even going to be added to the mix before the very slow demise of AA's operations over the past two decades there.