I wonder if the US government would allow UNITED or AA to start a new airline using US registered aircraft, with not one of those flight or cabin crew onboard holding US passports?
You know not of what you talk - this is unionised, nationalistic claptrap.
Most airlines the world over have employed local cabin crew at outstations - many still do as well. Besides, the flight crew have the right to live and work in the EU; the cabin crew however are logically US-based, located at what is effectively the hub of operations in JFK.
I recall when BA was allied to US Air, US Air operating a number of N-reg, BA-liveried aircraft to Charlotte, Philidephia and other routes, crewed by Gatwick Cabin crew, and US Air flight crew.
EC makes a great deal of sense with the IB merger, and will continue to do so.