This is definitely true, but I think it makes a good point. People these days (fans) think that 'rival' implies one team. Minnesota -> Wisconsin. I live in MN currently, this is really true about wisconsin. But IMO, a team can have many rivals. As an Iowa fan, I consider Minnesota, Wisconsin, ISU, Nebraska all to be rivals.
In fact, one thing I love about the way these new Big 10 divisions have been is that every team is a rival. Northwestern beats us every year, somehow. They're coach hates us badly. I consider them a rival. We beat Penn State very frequently, don't know what happened this year. I consider them a rival. We have had epic games against Michigan lately, and I consider them a rival (to an extent).
But Michigan fans would probably laugh at that. And narrow minded/uninformed college football fans would say that Ohio St is Michigan's rival (solely).
Among all the conference changes, that is what's cool about old conferences, rivalries. However, as 'little old Iowa' many teams probably don't consider us a rival because they claim to not care. We're not the flashiest, most popular program and those are the programs that people want to be rivals with.