On my earlier post Krishna from Google commented:
Ok, This may be true in most IT companies, but where i work (Google), this is not at all true. Good coders can choose not be a manager at all. In fact most people prefer to go the technical ladder than a managerial one :)
So maybe the pressure to grow into a managerial role may not be so high in a product company like Google, Yahoo or Microsoft but is it an inevitability in IT consulting or services firms ?