It's worth noting that several airlines have tried to serve Love over the years, with both large and RJ sized aircraft. AA flew super-80's to AUS and STL and failed miserably. The only two doing it today is United (to DEN and IAH) and Delta (to ATL and MEM), both in 50-seat RJs. Having been airlined on both carriers out of love, I can assure you the loads are light. Nothing prevents these airlines from serving additional destinations, as long as the number of seats is less than 56
Correction - UA dropped DEN a while back and DL switched MEM for ATL. There is no restriction on size to IAH being that it is inside the perimeter and often you will get CR7s flying the route.