The entirety of technology/engineering/materials advances over the last thousands years has had the net effect of making certain jobs obsolete or least needed in much smaller numbers. Buggy whip makers being the oft-cited example, but dyers, seamstresses, thatchers, brick makers, carpenters, etc... Automation, efficiency improvements, and material/product longevity increases all dramatically change the job landscape. And yet we're still employing the majority of an ever-expanding population. Things seem to simply shift around....