NYC has gasateria's (self service gas stations, before self service was the norm)
and a diner was a small coffee shop/eatery that started out as a dining car of of a train.. (i knew some diner that were just that!)
they often grew (adding on side dining rooms, (and eventually they got rid of the rail road car!)
in new york, greek diners (about 50% of them are still owned by greeks) set the standard for diner.. LOTS of food, good prices.. (think of the diner in sienfeld..)
greek diner set a high standard.. good food, lots of it, and low (relatively low) prices.
about 25 to 40% of the menu was greek food--
(i just came from breakfast at a greek diner-Fame on Union turnpike and utopia! (ah, i've been to utopia.. (and its not all its cracked up to be!)-breakfast was 4.50--for 2 eggs, toast, 8 oz of fresh squeezed OJ,(not a miserly 4 oz glass!) home fries, and all the coffee you could drink (3 cups)
(chain breakfast places often have cheaper 'specials' but don't include both coffee and OJ.. add them, and the price is much more!)
my local diner, (rego park diner) is transisioning.. the new owners (still buying the place) are south americans (and are using the place for bringing in family.. the wait staff all speak english, but the "bus boys" (adult men and women) are less proficient (but they only work at that job for 6 month to a year before moving on)
the old owner was greek (and he stops in every once in a while)
(its interesting how different ethnic groups gravitate to different jobs.. most of the gas station in queens are own by turks, (but in naussa(next county over) they are owned by persian(as they call them selves!)
Professional russians, (no matter what they did in USSR, run pharmacies..apparently most doctors find it easier to pass the test to be a pharmacist--and that's what they do.
(and a large percentage are owned by russian mob--who use the stores as fronts for money laundring, and to whole sale the drugs required for meth production.) (you can tell, all the stuff in the store gets dusty.. (low product turn over) but the store stays in business in high rent locations for years..