I am not sure if you are kidding, but the serious answer is that politicians who can stay in power without limits (witness Putin now) tend to rearrange the poli

I am not sure if you are kidding, but the serious answer is that politicians who can stay in power without limits (witness Putin now) tend to rearrange the political process of their country with sole purpose of never leaving their post. Then they lose all accountability and do as they please without worry of being voted out. Companies, on the other hand, exist in the ecosystem of the market (so a single CEO can not rearrange the playing field). If the company is doing poorly, its shares will drop and forces will gather to remove the CEO (note how Balmer or recent CSFB CEO were removed).