You don't have to be smart to be a manager. I mean in our(developer circles) definition of smart is some one who gets the job done. I mean the real job. Something that is of value. Most people managers don't do that.

In most corporates management really is book keeping. Managing vacations, leaves, holidays. Filling up appraisal sheets, expense documents, coordinating with HR, forwarding Information, arranging meetings and all these kind of assorted chores. This classifies under what you can call as 'running the affairs' as they are.

This has nothing to do building something awesome. That is a different territory. What managers in most companies do ideally is enforce sanity by bringing in mediocrity. Much of their work is in bringing in a process so that their life gets easier. They need numbers, so they have to deal and force people to do things like fill in time sheets, constantly update some system to keep the their managers alerted. You get the point?

Situation only gets worse because, sooner or later all managers realize- they hit a career dead end unless they are politically well connected within an organization to get that next promotion or a travel opportunity. In many ways they are forced to, their position encourages them to. Imagine having no coding skills, no ideas, no ways to show that you got something real done in years. Over time your own value in the market will fall down to point you know you can't really get any real work done any where. This is the story of many middle managers in big corporates.

Most managers are really cost and work accountants.