If you can put 18K in the stands, that is awesome. If the average ticket price was in the $20 range and the butts in the sets paid it - and didn't show up for free corporate-purchased tickets, that would be even better.
I have a very bad feeling about FBS non-P5 FB. With maybe $5,000 for "cost of attendance" stipends and another $5,000 for licensing rights per player, the P5 may be dropping $1 mill a year into the pockets of their players. If the non-P5 can't match that, they will be getting a lower tier of recruits.
The P5 look like they're going to basically become a minor league system for the NFL. In an odd turn of events, that could actually escalate FCS FB. It's possible that the P5 become the #1 attraction and BCS becomes the #2 attraction because that's the amateur system on an even playing field.
That could leave non-P5 FBS in some weird never-never land where they're neither relevant as a minor league for the NFL, nor are they relevant for any level of a national championship.
If you can continue putting 15K - 18K butts in seats, then maybe you're ready to move up to FBS. In that case, I wish you the best.