While I agree that not every black numbers operation popped up on the radar, cases such as the Dutch Schultz moving in and taking over the black numbers rackets in Harlem in the 1930s (later taken over from him by the Italians) or the Outfit moving in and taking over the black numbers rackets on the South Side in the 1950s are pretty well documented. When the blacks started trying to move in on Italian numbers rackets in Jersey in the 1960s, Anthony Accetturo and the Luccheses reportedly had several of them killed. Back then, the Mafia had both the political clout and muscle on the street that proved too much for any black operator they set their sights on.

Things would change in later years, eventually with the Mafia in places like Buffalo and Detroit ceding the numbers rackets to black operators. Even in New York 14 of the city's numbers operations were run by blacks by the the 1970s. Part of this was because of change among white bettors the Mafia directly serviced when sports betting began to become more popular than betting on the number.