The MAC is good at every sport. It's not just about being a "football community," those communities are better than other small communities at almost all sports (and academics). Go watch a few OHC boys basketball games, then go watch a few MAC games. Better yet, go watch some OHC GIRLS basketball games and then go watch the MAC girls. It almost looks like JV vs. Varsity as far as size goes. I'm sure hard work is a big part of it, and if you look at the state test scores of those schools, almost all are way up there, so they clearly have some of those intangibles you are talking about. But for whatever reason, there are some physical differences between the kids in Mercer County and those in Champaign County that cannot be solely contributed to hard work.
Mechanicsburg is definitely a football community. If you are going to say they aren't because they've had more success in bowling, then you'd have to call Minster a cross country community, Coldwater a baseball community, and St. Henry a volleyball community.