Other examples of Winston Churchill"s "Lean Thinking" are the following quotes:

"Every man should ask himself each day whether he is not too readily accepting negative solutions." June 22, 1918

He recognized the importance of root cause analysis and then the correct selection of the solution ( "A" in DMAIC).

Winston Churchill also understood the importance of identifying and defining the Value and Purpose in anything we do  ( the "D" in DMAIC )

"It is wonderful what great strides can be made when there is a resolute purpose behind them." 
May 7, 1947