North American Aviation, based in California, had several other Big $$$ Contracts going on at the time, IIRC, and Republic Aviation, based in Farmingdale, Long Island, NY, did not. Make of any of this what you will.
The cancellation of the F-107 and F-108 programs in the late 1950s, as well as the cancellation of the Navaho intercontinental cruise missile program, was a blow to North American from which it never fully recovered.
NA had some space program work as a sub-contractor. NA meager with Rockwell soon forming North American Rockwell.