Here is a great Dilbert cartoon that unfortunately describes the mentality of many, not just managers, in the exchange of ideas in the corporate environment. I think it is true that one can keep the subordinates or co-workers ignorant and powerless, but only for so long. Then, the brightest and best either dumb down, which harms the organization, or move on to other employers, which also hurts the company. In either case, the ones who win are the competitors.
I must say I am thankful this is not the case where I work! Thanks Sarah and Reed!!