I've never gotten why loquats aren't more popular as a grocery store fruit. When I've the pleasure of eating my own fruit after a mild winter/no late spring frost/biennialism, they were very tasty, even when not dead ripe. Call 'em cherry peaches! Or something...
BronxFigs, go to Edible Landscaping for loquat selection, tho' I don't think they sell Big Jim, which was the best when I was really into tropical fruits 20 years ago. Like figs, the leaves make a good tea. Like breba producing figs, the fruits sort of overwinter, after blooming in the fall. If the winter isn't too cold, then the major issue are frosts. No worries about fireblight in NYC, I think. I think it would be very unlikely that you'd be able to get much in terms of fruit.
Growing loquat seriously is probably more of a hassle than growing cherries, and I'd imagine that it does cost alot to harvest high quality fruits. No real effort is needed in warmer and frost free springs, and they're excellent for the home garden. In their natural range, in Florida, Louisiana, etc, they get very big, like old style apple trees, and drop more fruit than anyone can eat.