US won't leave. No capital to open another hub, a revenue elevator that is set to the basement in Philly starting in April, no capacity at PHL to make up the difference anyway. And they need the revenue that the fortress hub at PIT commands.
And, if they do leave, and the ACAA lowers the debt by $125 million or so, perhaps an airline with a bit of vision and a penchant for taking US profits (like LUV) would be interested. In fact, LUV has indicated as such in published remarks in the past.
Davey has a gun, but everybody at the table knows it is unloaded.