and where did you get that information?
DL has said NYC doesn't mean its profit target, not that it isn't profitable.
If DL can run a 400 flight/day operation at NYC and lose money doing so, push their nose into other carriers' key markets like SEA, and still post the highest profit in the history of aviation, then DL has a whole lot of bandwidth for going where it wants and be able to absorb a lot of losses.
Given that DL does have a plan for turning JFK- the part of its NYC operation that appears to be the bigger drag on corporate profits, I'd expect that DL will turn things around fairly quickly.
Remember also that the first phase of the LGA slot transfers began almost exactly two years ago.
Whether LGA did or didn't make money last year in its first year, the LGA buildup represented the largest single year growth in LGA history. Profits there and the spillover effect on JFK are bound to improve with time.
IF NYC isn't making money, DL's focus this year appears to be on the west. Either DL is content that NYC is fixing itself with the plans in place or they have enough money to use to develop the west and not deal with the NYC issues you seem to think exist.