Tennessee HS football isnt same as elsewhere in US. Yes, it has gotten better.
IOW, ¯\_(ツ_/¯
As the population of this country continues to shift, as in people from the North, such as Ohio or Michigan moving to middle Tennessee, then more and more high schools will be built and more football teams will be fielded.
In Nashville, alone, there are 84 people moving here each day. Not sure how many kids are in that stat or if it is merely college graduates moving here.