My major question would be where would B6/VX fly from AUS that isn't already a major operation for them? By that logic (and I'm not being dismissive here, just noting), AA has the makings of a hub here with mainline services to DFW/ORD/JFK/LAX/MIA/CLT/PHL/PHX (and if not for the perimeter rule we definitely would have at least one flight to DCA daily). And they even have the flight to LHR with BA, which AA has revenue sharing with BA on (and apparently LAX-AUS-LHR is a popular way to get to LHR now from LAX). But AA has no real motivation to start AUS-ZZZ where ZZZ isn't a hub for AA. The major reason to start a mid-con hub would be to better serve all of the other mid-con markets (i.e. STL, MCI, etc.), but B6/VX might just be better off serving those mid-con markets from their coastal hubs, rather than potentially spending a ton of money trying to make something happen at AUS. And WN would likely dump major amounts of capacity if B6/VX pushed too hard.