The commonly held belief is that in any company you need workers (people who do the work) and people who decide what to do. In other words, you need not so bright people who are happy to plug away at their keyboards, the "workers" and you need the intellectuals, people who guide the workers and leverage their value. That is the common view, probably wins the day mostly because you can't find enough "intellectuals", and you can't afford to pay a bunch of intellectuals their full value.
Look up http://www.thoughtworks.com. Started by someone who said no, and created a company of _only_ intellectuals.
But I digress. My Father has always talked about the difference between a manager and supervisor. He's said a _manager_ is an agent of change and a supervisor maintains status quo. Most of the managers in even our top companies are in fact super-visors. This is especially true in middle management. Pnp was a good example of this kind of manager. He has recently been mulling over the idea that leadership and management are not the same thing. This he says is what the cognscenti have recently been coming up with. And he has a point. A leader is someone who inspires, they have vision and drive. Just by sheer circumstantial evidence it is obvious that a manager is not necessarily a leader. I have found that a leader is more effective when they're perceived to be on the same level as the people they're leading. Kinda like the way you have NCO's in the army. They are some of the most important people in the army because they're on the ground. The infantry feel far more loyalty to the NCO's than the officers.
The other thing I wanted to say is that the difference between a manager/leader and worker is not intellectual or in ability. It is in _attitude_. Managers need to have the "can do" attitude. That attitude that says "cool, let's do it", instead of the "why do that?, that's a silly idea". It's question of how big is your world.