Interviewing isn't just a measure of how good you are at programming in real life. It's how good of an employee you will be. Conformity is a strong indicator of this. Comparing someone who completed a CS degree versus some guy that learned to program in a garage hacking together broken computer parts - the employer is going to choose the CS degree guy, even if the hacker is better at programming. CS degree means you follow direction, you can work within a rigid structure, you follow rules enough to make good grades and not get kicked out, and you're capable of doing monotonous work that sometimes has very little value.