Let us not forget that in "The Effective Executive" Drucker assumes a rather idiosyncratic definition of the term "executive", which is "every knowledge worker [who] is responsible for a contribution that materially affects the capacity of the organization to perform and to obtain results".
Time demands on the knowledge workers are not going down. Machine tenders now work only forty hours a week — and soon may work only thirty-five and live better than anybody ever lived before, no matter how much he worked or how rich he was. But the machine tender's leisure is inescapably being paid for by the knowledge worker's longer hours. It is not the executives who have a problem of spending their leisure time in the industrial countries of the world today. On the contrary, they are working everywhere longer hours and have greater demands on their time to satisfy. And the executive time scarcity is bound to become worse rather than better.