It matters to the NCAA - may not make sense, but it holds us and others back (not that we don't hold ourselves back anyway)
The rule that the NCAA has in place for attendance is not enforced like it could be. If it were enforced, EMU would have lost FBS status a long time ago based on their average attendance numbers. In fact, there used to be a rule on stadium size as well where your stadium had to seat at least 25,000 patrons. Ohio would have been ineligible in this case since Peden only seats 24,000. I believe that rule has been done away with however, and the only thing counted as far as attendance goes is a once every two year requirement on a rolling basis that you average 15,000 at your home games. No way EMU has come close to that.
That rule was to have a 30,000 seat stadium or average 17,000 in attendance once every four years. Ohio pre-Grobe was drawing about like Ball State 9,000-10,000. The design then came out for a 30,000 seat Peden Stadium to meet the requirement and that was partially why the school expanded from 20,000 to 24,000 seats in 2001 to take the school a step closer to meeting that 30,000 seat requirement. That seating requirement was eliminated 5-6 years ago and the overall attendance mark was lowered to 15,000. Since that time several stadiums across the MAC have downsized from 30,000. Miami, BG and Kent State all had 30,000 seats with endzone bleachers. Miami and BG reduced to 23-24k with renovations and Kent State dropped all the way back to 20,500. Since the rule for stadium size has gone away, the defacto standard for an entry level FBS program has become 25,000 seats. That gives a program plenty enough capacity to meet that 15,000 requirement. Eastern Michigan's 30,000 seat stadium was a byproduct of the 30,000 seat rule and because they made the entire stadium permanent seating they can't unfortunately downsize to something in the low 20's.