The area between Des Moines and Ames is seeing the beginnings of incredible growth. Ankeny is obviously going to be the big driver for the next 20 years, but keep an eye on places like Polk City, Huxley, and Bondurant.
As Ankeny and Ames grow towards 6-figure populations, more people will look outside of those boundaries for a "nice, small community" to raise their family. It's already happening.
In 2010, Polk City, Huxley, and Bondurant had a combined population of 10,000. Now they are pushing 15,000. That's 5-6% annual growth. Towns that size do not organically grow at that rate, if at all. It is a 2nd ring of suburban growth - suburbs of the suburbs. By the time Ankeny and Ames are > 100k, each of those three towns will probably be in the 10-20k range themselves. Drive through those towns or browse the real estate ads and you will see new construction and housing developments springing up. Even the tiny towns (Slater/Sheldahl, Alleman, and Elkhart) are seeing population growth. In 20 years, the entire area (Ankeny to Ames) could be upwards of 300k people within 20 minutes of Iowa State.
All that said, I would certainly hope that ISU would make an investment to ensure that the area of southern Story County and northern Polk County becomes a stronghold of Cyclone fans and supporters, similar to the way that the area between Cedar Rapids and Iowa City is Hawkeye Country. The growth has already started and there's so much potential yet to be realized.