And yet somehow the employment and unemployment rates in the developed world are pretty healthy, and there are more manufacturing jobs in the developing world than ever.

The point of technology is to reduce the number of people doing a given task, freeing up that labor to perform higher value activities, or the same activity to a higher value. So fewer people need to be sailors, road work gang members or field laborers and more of us can be TV presenters, computer game artists and SCUBA diving instructors. Occupations representative of whole industries the world couldn't have afforded to support a hundred years ago. Vast swathes of the population back then were doing jobs that hardly even exist anymore, yet somehow we don't have vast swathes of the population out of work. That doesn't even factor in the massive transfer of female labor from household work to the working class and professional labor markets.