I do not believe that university fullfills a really good role when it comes to filtering for intelligence, it rather filters for familys who put pressure to preservere on kids. But they do a really good job, on forcing people through stuff, that a self-tought person might skip- because they found it useless or not applicable. Algorithm theory and the limits of computation? That is a dry topic and tough to get through without beeing forced too. Software-architecture? Cant see me using that- those small projects i worked on always worked well without. And so on and so forth.
University does one thing right, it forces you to be interested in stuff you do not know you should be interested in.
I do find the filtering out of people who go to university - either by school grades or by monetary parent background really nasty though. In my eyes, anyone who is shown to apply himself, should be able to stay at a higher education.