First, less quality opponents coming to LES and no conference race reduces season ticket demand.
Second, there's that deflated feeling of "even if we're perfect we could wind up with a lump of coal" and we've only been perfect once in our history. Not that winning the MWC and going to the Liberty bowl was an amazing reward back in the day, but at least you were the champion of something and could rub it in conference foe's faces.
Having said that, the good opponents (at least) should be sellouts if we're serious about supporting the program.