Makes absolutely no market sense. There is just too much competition especially for NYC!
I can't see JFK lasting longer than 1 year. You can get more for cheaper with other carriers. I still think people will choose to transit via LHR with the likes of BA.
I can only think that it might be more appetising than travelling across in that terrible AA 757 on the direct MAN-JFK.
But in all seriousness, very surprised and do not think it'll last at all.