I agree with others here in saying you must have a product first, particularly when considering your area.
NYC is one thing, but Brooklyn is another. It could be argued that Brooklyn is the Kingdom of Heaven when it comes to pizza: Totonno's Coney Island, L&B Spumoni Gardens, DiFara, Motorino Williamsburg, Paulie Gee's, Lucali, Roberta's, Toby's Public House, Grimaldi's, South Brooklyn Pizza, etc, etc. The list of better than average to great pizza joints that immediately springs to mind in Brooklyn is unbelievable. Generally, what distinguishes places like these is that their product stands out.
We could all argue for days whether pizzeria "x" is "great" or not, but (for example), I don't think many people would call Totonno's Coney Island a crappy pizza. Granted, they have a coal oven to tie into the lore of the whole NYC coal oven pizzeria mystique and a history of some quirky pizzamakers and owners, but a lot of the reason for the continued success and perception of Totonno's is because of the pizza itself. Ditto for DiFara. Yes, people come to be in close proximity to Mr. DeMarco, but generally people come to DiFara because of the product. And neither Totonno's or DiFara are close to Manhattan (40min to 1hr subway ride), yet people visiting Manhattan make the trek out to these places by the dozens because of tales of great pizza.
And while (in my opinion) a place like Roberta's does not serve a "great" pizza, they do serve much better than average pizza and add in one of the cooler spaces (outside seating, DIY ethic; have their own gardens outside and are adding laying hens as well!) and it's a good place to spend time in. But again, while the space is interesting and other food items than pizza are served, the product (pizza) itself is a good, solid product with creative toppings that enhances the fact there is a cool space there. It takes more than just a space.
I think the marketing and intellectual property of the bigger chains works well and influences buying decisions in other areas of the country. Particularly rural areas and many cities where there is not so many pizzerias per capita and/or in areas without a long standing, embedded pizza culture (as in most of the country). But NYC is definitely different. While I would argue that there is nowhere else in the country with such a high number of mediocre pizza joints, New Yorkers by and large cannot be bullshitted when it comes to pizza.
A few of the pizzeria's I listed above had minimal traditional marketing at all.....purely word of mouth, smart use of the internet and blogs and other very low cost guerrilla marketing techniques. Those same pizzerias either did or will make a profit much sooner than most would think. Without the deep pockets of a big corporate chain or fancy advertising campaigns, a good amount of the newish, artisinal pizza places are making headwaves in a very competitive market. What generated the grass roots excitement and continued patronage of these places is the very same thing that still draws people to places like Totonno's and DiFara -- tales of great pizza.
With the sheer volume of people living in NYC (Brooklyn alone would be the country's 5th largest city if it was its own municipality separate from NYC), given a good location and lots of other factors which I don't pretend to know, there is always room for much better than average pizza. Good luck --K
