Prehaps entrepreneurs should stop reading and start doing. Some things are just impossible to learn from a book, and even the things that can be learned from a book can be learned faster and better through personal experience.
That's way too broad and general. The problems that hit entrepreneurs along the way are often things they don't know they should be learning before it's too late. By that point, the only thing you're learning from is your mistakes, and that's no way to learn if you can avoid it.