Have said it for years that the contributing factors for football taking off in Charlotte area were (in no particular order) 1/ population growth of people moving from out of the area. 2/ explosion of youth football. 3/ Panthers. 4/ former NFL players establishing Charlotte as home creating more personal training for football, stength, and skills. 5/ Tom Knotts.
Sheer population growth resulted in more schools but more talent to choose from. In 1998 Providence was the eleventh public high school in the county. Today there are 19 schools with football. The quality of the private school football has increased tremendously.
Youth football is big every where but was rolling big in Charlotte in the mid 1990's and very much so in the early 2000's. Mint Hill and Matthews both took off in that time frame stocking Butler and Indy teams during their runs.
The facilities and "professionals" offering skill development, especially for QBs, and S&C is huge in the area.
Panthers brought even more interest to the sport and the NFL. It's a big deal when a Panther visits an elementary school, holding camps in the neighborhoods, supporting youth programs, et al. Having "your" team made it more special. Those guys were in town.
Players from early Panther teams retired and became part of the communuty. Other NFLers NBA players started calling the area home during the off season or after their playing career. Some players families stayed here year around. Those retired players got involved in youth sports and other businesses that often supported programs.
I am in agreement that Knotts made others step up their game when he went to West Charlotte and later Indy. You had to change or get embarrassed. He was innovative and won. Took awhile to get over the hump and get his first state title (days before subdividing!) but was in the hunt every year.
Today and over the last several years a big part of it has been some very good high school coaching, both HC's and assistants. Long line of them but must retain them.