As for why NYC has so many great straight pool players, I can think of a couple of reasons. One, the game is still popular in NY, so it's easy to find a game. Here in SC they don't even know what straight pool is. Tonight in fact I played straight pool with a guy from Baltimore, and several people came by and asked what we were playing. These were regulars. They had never even seen a straight pool game!
A second reason for the NYC area producing many exceptional straight pool players is it was so easy to see top flight straight pool played. For example, back in the late 80's and early 90's, you could walk into Chelsea Billiards and watch George Mikula nearly every afternoon run 100 balls two or three times, even 200 was not uncommon. A little later in the day, Johnny Ervolino would stroll in and slip-stroke his way to 100 ball runs. In addition to those guys, there were plenty of shortstops who would regularly put up 100 ball runs. As well as countless guys who routinely hit 50 or more.
So in NYC we got to see a lot of really fine straight pool, see how those guys would pattern balls and take care of trouble situations. And we'd talk straight pool a lot. When I play now, I still hear Ervolino's scratchy voice telling me for the hundredth time, "It's an easier game if you keep your last few balls above the break ball." And the vision of George's three ball diamond pattern for getting on the breakball. I saw him do it so many times it's burned into my consciousness.
I spent most of my time in Manhattan pool rooms, but Queens had Gene Nagy and Danny Barooti (sp?), Brooklyn had Tony Robles and a bunch more I've forgotten, and just across the river in Elizabeth, NJ you had West End Billiards where on any given night you might see Mizerak, Hopkins, Colavita, Ray Martin, Neptune Joe, Harvey Martin and so on.
With all those great players to learn from, the NYC area, therefore, has a long history as the Ph.D factory of straight pool.