You cant be this obtuse. Factory employment incresed in many years after WWII. From 48 till 58 it increased untill the 58 recession took its toll. From 61-69 it increased, from 71 till 73 it increased untill the Arab oil embargo collapsed Americas industrial sector, from 75-78 it increased, from 82-87 factory employment increased and from 92-99 it increased every year.
Factory employment has DECLINED WORLDWIDE! Even China has seen the percentage of its workforce involved in manufacturing decline. Like it or not, you folks who idealize "smokestack America" (when Democrats ruled the world, btw) have got to wake up to the fact that we live in a white collar, service oriented world. The folks who bemoan the loss of the industrial economy are no different from those fogeys who lamented the loss of the "yeoman farmer" a century ago.
I suspect you are confusing "manufacturing output" with "factory employment." Manufacturing output has increased almost every year since World War II, but manufacturing employment has not. Constant advances in technology and improvements in productivity have made it possible to manufacture more things with fewer workers over time.
Even China has seen a dramatic decline in factory employment in recent years, despite dramatic increases in factory output over that same period.