[rrrrrrrrrrrryan]

It's because business skills are mostly learn-by-doing skills. No matter how many books you read about bicycle riding techniques, you're not going to ever be able to do it unless you've actually given it a try and scuffed your knees a bit.

Not all skills are like this, of course - you probably want your doctors and scientists to be people who actually read the textbooks and paid attention to their professors.