Actually, not any more, TIS. When I was growing up, Jews constituted almost a third of residents of the five boroughs of NYC. In my old neighborhood, Brownsville Brooklyn, there was a kosher deli literally on every corner. Today the Jewish population has shifted elsewhere, and they've discovered Chinese and Italian food.
Meanwhile, the population as a whole has embraced Jewish deli (as seen in this thread). You can get decent "Kosher-style" corned beef, pastrami, tongue, brisket and matzoh ball soup in plenty of places, not all of them in Jewish-operated restaurants. But the hardest-to-get authentic Jewish soul food is really good derma (kishka). I'm talking about the derma that's grayish-brown, not bright orange; firm-textured, not mushy, and that comes with gravy that's actually viscous, not like spackle. Try finding that today.