The things frequently asked for, brunch spots, hip bars, trendy burger joints et cetera, are distinctly American in culture, with the preponderance (not all of course!) of their patrons being younger, native born and wealthier (and I'd venture zero dependents, but that can be folded into disposable wealth). We have a large percentage of folks over 65 here, as well as a % of foreign born which is towering even by NYC standards and many families with many kids. Frankly, I think they have more to do with it than income levels.
JH is a very densely populated hood, and by absolute numbers, there is a kernel of folks who could support such establishments. Problem is the nose of the investment dollar, in particularly with risky businesses like eateries. Quit the day job, pull in the life savings, put it all on the line for the 10% willing to pay $12 for an eggs benedict or the 50% willing to pay $24 for a good parilla? People keep pointing to Starbucks, but Starbucks is a chain and chains can better weather risk. And if you make that great waffles and chicken, why come to JH? The only reason why you'd do it is because no one else is doing it, rather than setting up shop where rum soaked jalapeno goat cheese poppers are not so niche. No one is saying it can't be done, its just awfully hard and money is like water, it generally follows the easiest path. For individual shops with individual character, it takes a person with some balls.
And its not just your balls, but also the landlord's balls. When Peter Moceo wanted to open Rice to Riches, finding a space was difficult because no landlord thought that a place which only sold rice pudding could make their rent. Landlords want a steady, stable tenant. Hats off that he defied the odds and made a go of it, but he is the exception. In Jackson Heights 2015, the odds are on a Seba Seba rather than a Hope & Anchor. When the demographics change, so do the odds (Moceo was arrested and may have used his shop to launder money, so maybe we can get a li'l coke and cupcakes thing working).