NYC is the best place to live/work if you don't plan on having children, which is the ultimate arbiter of whether a given environment is indeed "good for young people" or not. If it wasn't for the flood of people moving into NYC from regions where people still have kids at higher rates, the entire city's population would quickly collapse. It's a genetic graveyard.
That New York's fertility rate is abysmal is not "completely false", it is an objective fact.
Whether you think New York is a "great place to have kids" is completely beside the point. What matters is whether the people in NYC actually have those kids, and at what rate. In New York, not enough of them are born to make the city a viable concern if it were not for massive population infusions from elsewhere. NYC is a population sink.
Best wishes to you.
Maybe if NYC builds artifical skiing slope, or nice sandy beach..
Is Meadowlands too far away ?