<p>It is a cyclic thing. The better the student population, the higher level the classes can be taught at. The higher level classes produce better graduates. The reputation builds. The better the reputation, the better profs they can attract, the better the student applicants are and the more money they can charge (both the students and for their research capabilities as all the top schools are also big research unversities). Opps, the circle ended at money.</p>