I'm from small-town Iowa and like you we had full rosters and a full gym for all the sports. But we didn't have much else for entertainment....
There are some good kids programs. But a lot of districts don't have middle school wrestling and that hurts. Few or no duals makes it hard to generate student support. Kids will gladly bug out of the house on Wednesday night to go to a school-sponsored event, but to dedicate a Saturday...not so much. Without students in the stands, the crowds are pretty small.
It's hard to fathom that large schools would have an empty Varsity slot...but its common. I think its because the sport is just too demanding for today's youth. Getting a "letter" is no big deal. Do they even have "letter jackets" anymore? I guess I've seem a few. Also, some coaches I talked to can't keep kids eligible. If they are flunking classes they end up off the team. That policy might be outdated.
There is also the "Rule 10" coach problem, and I don't know how big a deal that is because I don't know how many Rule 10 coaches (coaches who do not teach in that school). Having a coach/teacher in the building makes it much, much easier to recruit kids for the team, particularly if the teacher is well-liked.
I don't know about the cost of admission running people off. Maybe some, but gas used to be 32 cents a gallon, for ethyl, and now its more. I still cruise the four lane.
