"Why in the world are schools building new buildings? What is required in a business school classroom that is any different than the classroom for psychology or sociology or english or any other number of classes?"

This question is easy to answer. In a time of declining public funds universities are trying to attract students, because tuition is about the only funding source left. Consequently, universities have to look appealing to students, and that means cushy dorms, spiffy libraries, the lot.

Again: these are investments made from the general fund, and the university tries to recover these through increased tuition income. A classic market failure.