LNIDA that's scaremongering with stilts. Emirates have a fortress hub in Dubai which they increasingly fly to the US direct with, anything else is tinkering around the edges. Your claim that IAG are afraid of LHR expansion is so far off the mark as to be fanciful. If EK did launch MAN-NYC, they might knock one of the US carriers off the route and screw ongoing connectivity for MAN pax in doing so. Result!!! Er not.
Careful what you wish for methinks.