I think it is all over.
I predict they will never be able to get their costs under control. While the pilots union has agreed to switch to RJs, the reality is by the time US takes delivery of these planes and deploys them, it may be too late. Plus, I can't see ALPA ever making a concession beyond this one. This is just one concession of 3 the airline needs, and lower wages and more hours just doesn't seem to fit the bill.
Even if US did get its cost down, it will still crash because the low fares will just keep eating away at US. Looking ahead, once Air Tran and WN and maybe Jetblue get a little more established, there is absolutely no reason to fly US on the east coast. Who is going to fly through PIT or PHL or CLT just to go 500 miles? When you can go nonstop on the others? And if US does try to match the others in more point to point, it will begin to alienate itself at its own hubs. A huge catch 22.
Like HP, it is interesting to wonder why US didn't see this all coming in the 80s when it went on that shopping spree of Piedmont and PSA.
Another point, there is no reason to fly US to Europe either. Most of the pax are O&D or around the Ohio, Great Lakes and mid-Atlantic area. Given the right environment, these same pax can easily just switch over to a CO, DL, AA or UA for their Trans Atlantic needs.