I too believe that it is a combination of reasons. I think the biggest is the lack of jobs in the area other than coal mining. The need for manufacturing and other service related jobs contribute but you can't get those in the area because of the lack of access to the major transportation hubs (Highways, Railways and airports). There is also not a lot of tourist related jobs because of the lack of attractions and again the roads. The other reason falls on the access to tv, videos, and electronic games. Disappearing are the days when a bunch of kids get together at "Johnny's House" to play football or baseball and even basketball.
I too am one of those that left the area because of work and was gone for almost 30 yrs. I did return for a couple of years but there was nothing there and the crime and drug problems are bad. So with that you can't attract anything. Now I live out of state in an area where we can't build houses, apartments and schools fast enough because of the growth. The football programs (and baseball) programs have a lot of participation. And yes a bigger number of D1 and D2 level players (plus it seems that they grow bigger down here). They have a spring football practices and 7 on 7 games.