But you don’t know it could make a profit, nor does anyone.
I also don’t understand how you can compare Dubai to New York.
EK has an enormous global network of connections out of Dubai which brings business as well as leisure pax. A NY flight of course would have some business pax on board however the majority will be on packages of 4-7 day sightseeing holidays to New York, travelling in discounted economy fare buckets – the demand may be there yes, but profit, I’m not so sure.
Also, EK has significantly lower costs than any US airline. There are very little, if any, human rights in the UAE, there is no minimum wage (and an average 48 hour work week), fuel is cheaper and then ancillary costs even as small as catering production are cheaper there. These factors are a large part of the reason EK are so successful – they can price many competitors out of the market. The bottom line is that the majority of people book flights based on price; if that means having to one-stop through LHR, AMS, CDG etc over a nonstop then the vast majority would do so to save a bit of money. I just can't see a US airline making a flight economically viable.
What also needs taking into account is the inbound traffic. Newcastle city is a nice place but it’s hardly a tourist hotspot for Americans – the flight may be full of outgoing visitors but may have little inbound traffic, something which the likes of LHR, MAN, EDI etc bring.
There are also other reasons but I don’t want to thread drift even more…