What value does a consultant add to organizations?

I think most companies are too close to their operations to see it from a distance and understand it in a larger perspective. To give a simple example, the sales personnel are very close to the product service they sell. They just keep on thinking why their product should be bought. Thus it becomes very difficult to think "why their product/servicer" can not be bought. The reverse of the situation is equally true.. they become very pessimistic about the product. Unless sales people are aware of both reasons, it is very difficult to design a sales startegy. This is where consultant can come into play.. who can impartially look at the scenario from a distance and add value. This kind of work is very interesting and useful for the client. Probably this is why most professionals enjoy being a consultant.