This business of "moving to profitable flying" did not work in California, nor did it work at BWI, nor in Florida. The run and hide routine has never worked.
The funny thing about all of this is two little things which are often overlooked:
1. PIT's O&D is greater than CLTs, and climbing (it's higher than it ever was during the US hub days). By the looks of the airport when I go thru (which I don't all that often anymore since I don't live up there), O&D has gone up a lot.
2. When US East was printing money, PIT had 500 flights/day. That's with labor costs that were not artificially lowered by BK, BTW.
You have to connect people somewhere. If nobody goes to PIT, even fewer go to CLT. And PHL is a shithole for connections (and nothing will ever change that).
But hey--I'm sure the US' customer base will continue to come back meltdown after meltdown in PHL. Or having to fly LGA-IND via CLT to ensure their luggage (and them) actually make it.