AA does not fly JFK-AUS nonstop. Perhaps you're looking at jetBlue? As you probably know, AA has long flown direct (not nonstop, but direct one-stop) flights from LGA to AUS with a stop at DFW (currently) and, in the past, LGA-HOU/IAH-AUS. That's because the LGA perimeter does not allow nonstop flights to AUS from LGA.
For much of the past 20 years, AA has flown very few (sometimes not a single one) flights between ORD and JFK. When someone asked "why doesn't AA fly ORD-JFK nonstops?" the answer was usually because there were no international destinations from JFK that could not be reached from ORD or DFW. The only reason AA would have to fly pasengers from Houston to JFK would be to fly on an international flight from JFK that you could not reach from DFW or ORD. There may be one or two flights that meet that description, and if so, AA has determined that Houston passengers aren't sufficient for a Houston-JFK flight.
Of course, AA has long flown numerous daily LGA-ORD/DFW flights to capture the large NYC O&D market. Passengers in NYC who want to go to Houston have numerous choices from LGA and EWR to both HOU and IAH, just not on AA. Why not AA? AA is currently the highest-cost provider (and will be until the bankruptcy trims expenses) and the fact that Houston and Newark are the largest UA/CO hubs. UA doesn't maintain a very extensive schedule between DFW and MIA, two large AA hubs. Although things may have changed recently, for a while, UA did not fly mainline planes between ORD and MIA or between ORD and DFW, also large AA hub pairs. Ted may have flown to MIA and UA flew a few RJs between ORD and DFW.
B6 is a low-cost airline that captures the few who are willing to fly from JFK. Once AA reduces its expenses, perhaps it would make sense to fly LGA-Houston again. If AA enlarges its international flight offerings from JFK to cities not served from ORD or DFW or MIA, then perhaps a limited JFK-Houston schedule would make sense.
AA's JFK flights to LAS, MCO and TPA primarily exist to connect international passengers to those popular destinations, not because AA is targeting the domestic O&D. Houston is a fun city, but it's not at the top of the list for AA's international customers.
I realize that this post goes beyond the OP's "Dots on the Map" analysis, and for that I apologize.
-D.....ok, ok ALL of ya stop it... other mechs are looking at me "wth"?? 
