Since the Deep South didn't have a pro football team until the 1960s, the college teams became that location's "pro team" in terms of interest. As a result, it help feed the "desire" for the sport at the lower levels and even increase the level of competition at the HS level within the state. Over time it morphed into a "religion" of sorts.

Another possible factor is there are a lot more large urban areas in the NE (aka large cities) than in the Deep South. So available land for youth, HS, and maybe even college football may tougher to come by than available for outdoor basketball and tennis courts. I am thinking in terms of the early 1900s when football was just starting out.