I agree with you basic theme that Leaders need to produce. However I also believe that sustainable leadership is only possible when the Leader has the ability to tap into the collective genius of the people he/she leads and produce through the followers new ideas, solutions to problems etc.  Leaders are measured by their output, but they should also be measured by the output of the group or organization they lead.  If all the production comes only from the leader with the group acting just as the implementers, the leadership model is not sustainable.