I have always found the university ranking game to be screwed up.
Are the best Universities good because they have the best teaching, or are they just selecting the best people, who would be successfull no matter what?
The universities are penalised in rankings when a student fails to pass, but they are not penalised if they are so selective that the student never got a chance to study in the first place. This breeds an elitist system that does not let students rise to the challenge. Thats also one of the reasons why european universities do worse in rabking than UK ones - it's common there to start with a huge class, but only small part will co plete the course. In UK its harder to get in, but vast majorty seems to pass.
If universities worked like a normal business does, you'd expect that the best universities would grow, expand, and eventually there would an Oxford in every major city, with oxford teaching methods. But that's not how it works. But people still keep trying to appply 'free market theory' to education, when it obviously works very differently.
Lastly there is perpetual conflict between research and teaching - many professors want to do research and don't like teaching, many post graduate teaching assistants are folks that, no matter how briliant, were afraid of the job market, etc.