When the boss is responsible for managing, you often get subordinates hiding problems. It's hard to hide things from peers. If you screwed up, well, that helps me to look better. But if we say we're all responsible for the whole, I'm not going to let you screw up. And a third is that a powered-up organization is a learning organization.
Managers tend to be great individual problem solvers but lousy group problem solvers.
Let's say we go into a meeting and we have a problem. Most managers show up with a solution. So we start arm wrestling over which decision is best. We may compromise and put something together, but that's different from real problem solving. Problem solving works only if I don't have the answer.