It operates from some of the most expensive airports in the nation, which prior to the recession and 9/11 were chronically clogged, like LGA, BOS, and DCA.
I really have to disagree with you there. These airports are chronically clogged for a reason, namely people and more importantly business people and politicians are willing to pay for the privilege of using them, and using them frequently and consistently.
U's real strength is the point to point, niche flying they do rather than pure hub and spoke connections that most other airlines use exclusively. Example: From DCA (prior to 9/11) U flew to: MCI, BDL, HSV, IND, MSY, PBI, PVD, RDU, TPA, CRW, CAE, DAY, JAX, TYS, SDF, BNA, ORF, ALB, ABE, BWI, BHM, BUF, BTV, GSO, GSP, MHT, MGW, HVN, PWM, ROC, SAV, SYR, RIC, ROA, SBY, and HPN, ATL, CMH in addition to PIT/CLT/PHL and the hourly shuttle to BOS and LGA. No other airline even comes close.
Regarding the F100's---they allow US to make a presence in markets where other airlines are flying props or RJ's by offering a true 2-class service in a real plane. Markets like Erie, PA or TRI for example.