Don't forget that some companies only recruit at certain schools. That's how I was hired. Someone from another, lesser-known school might still have all the requirements to be successful, but it's an example of a door that opens much easier when you're in a formal university, as opposed to hustling your way into a position.
I saw that in law school. Certain law firms will only recruit or take resumes from certain schools. Unless you are at the top of your class at a lower-ranked school, your resume automatically goes into the trash.
Employers are playing the odds- they know that if they interview 10 graduates of U of M engineering school, for example, a large percentage of them will meet the needs of that employer simply because they have been pre-screened by the school for intelligence and work ethic. With someone from a less prestigious school, or who does not have a degree, they aren't getting that pre-screening process.