As others have mentioned, you can't grow the program if people aren't willing to grow. If everyone who was ever a donor had locked in their contributions at whatever level they were 30 years ago and not adjusted for inflation, we'd be a D1AA school, if that.
You don't go to the car dealer and insist on only paying what a new car was worth 30 years ago for a 2008 model, even if the 1978 (holy crap I'm going to be 30 this year!) model did the same basic stuff as the 2008 model. Times change, and life moves on. You can still get a used car for the price of a new 1978 car, but it's not going to be a brand spanking new 2008 model.
At the end of the day, ISU football IS a business. You can make it personal, just like people make other companies personal (Apple, for instance), but they exist to make money, in the case of ISU to support growth as well as the other non-revenue sports.
If ISU athletics is to grow, it needs more money. Period. Your 100 dollars a year is worth 5x less towards that goal that the person that will be sitting in those seats now. That's life. It stinks. You can have sour grapes about it, or you can suck it up and move over a section or two and still support ISU football, which is why you're there in the first place, right?
NOTE: The "suck it up" comment is not implying that anyone should or shouldnt' spend money in any way they do or do not see fit. You can obviously keep the donation level the same, but you're not going to get the same seats. If that value proposition isn't worth it to you, then so be it, but that's simply the way it is.