KN,
To try to answer your very valid points, here goes. US airline union contracts have section on "scope of work" which defines, really restricts. Who will do what flying. The ompany's agreement is all flying will be done with pilots under the contract subject to some exceptions. For example, the ALPA contract at Delta says all flying done by the Corporation will be flown by pilots on the DL seniority list. The exceptions are for up to 450 regional jets of all sizes, of which, only 325 can be of 76 seats weighing no more than 86,000 pounds. There are also provisions for joint ventures like AF on specific routes and similarily with Alaska on specific routes with limits on passengers carried. It used to be very simple--all flying was done by ALPA pilots, period, but bankruptcies up paid to those contracts.
I agree that theoretically the companies here could do contracts, but it just isn't done here for reasons that might be cultural more than anything. Remember, any non-union employees here are employed at the discretion of the employer. If XYZ airline hired its own employees, they could fire any pilot they wanted without much restriction from the government. No need to contract out.
Yes, NULH and all the others are going to hurt all "legacy" carriers as long as cheap labor is there.
GF