NYC AM's (the 50KW variety) may cover a lot of territory, but so does the NYC metro area. Get outside of the metro and how strong are those stations? The area doesn't have the best conductivity. Chicago does and you probably will end up listening to their 50kw AM's for quite a while. Back to NYC, even if the FM's are still there, by that point you're probably listening to stronger signals from these smaller towns outside the metro. By the time you get out of the metro area, you have powerlines, semi tractor-trailers and other things causing interference on the dial. Even certain brands of cars have things in them that can cause interference to a local AM that would make you not want to listen. Even when those cars are turned off, the interference is still there. While they may be quieter areas, other than people like me who can put up with AM interference, most would tune out by then.