motivation to go do such things, no young athlete is going to go sacrifice two years doing something like that, even if it would have made him a better football player after coming home (which it wouldn't).

You want to go play for Nick Saban, but Saban wants to send you off to Africa for a couple years? Now you're saying hello to the best programs that won't send you off, and Saban loses all his recruits.

But, still, it's a moot point because a program trying to balance the scholarships, timing, reconditioning, and change of priorities of athletes who serve missions is not gaining enough an advantage to make that effort worth it, football-wise.