I think US has explicitly made up its mind already by dropping the route.
While I am all for the "screwing" to happen - I dont think anything would make them change their mind (if you believe their publicly stated rationale). And the money these companies had already been spending on their employee travel was already "on the table" when they walked away. If they want to let US reconsider I am all for it, but I dont see it happening. I cant imagine these $10MM guarantees are significantly better than the situation they had before they yanked the route.
Ironically, US will make money if LH comes in - both from possible connecting flights and also the fact that PIT-FRA would be a codeshare. They could make money booking people on the flight without operating it themselves.
To them, they probably see this as a best case outcome. Shortsighted perhaps.
Btw, havent seen anyone respond to my cargo comments above - anyone have any data or info on who the big contract users were?