ISU on the other hand is a public school which costs less to attend so the administration does not have to fight to keep a steady enrollment, I'm sure the women at this point out number the men (pure guess), women tend to not follow sports as rabid as men and BN probably does not have as many ISU alumnus as Peoria has Bradley alumnus. Two total different cultures in central Illinois and that is why I'm glad to be on the BU's side of the fence.
Some of what you say is true, but I would note that Bradley now has more females than male students, too. That was always true at ISU, but has only been true at Bradley for the last few years.
And there are many more ISU grads in the central Illinois area than there are Bradley grads. Most BU students are not from the Peoria area, and thus they are more likely to leave the area after they graduate. But a much larger percentage of ISU students are from the central Illinois area, and coupled with the fact that attendance at ISU is more than 3 times what it is at Bradley, a far larger number of ISU students stay in this area after graduation.
There are probably many other factors that affect attendance. But suffice to say that Bradley gets better fan support than ISU, outdraws them every year, and has a much more loyal fan base. That could change, but as long as Bradley fields a quality team, it isn't likely to.
In general, college sports are seeing a decline in attendance at live events. It has to do with a lot of factors such as the quantity and variety of available sports on TV, other entertainment options available to young fans, the economy, the fact that the population is so much more mobile that it was a generation ago.