That's such a economical fallacy that I'd expect the HN crowd to have understood this ages ago.
Compare the average productivity of somebody working in a car factory 80 years ago with somebody today. How many person-hours did it take then and how many does it take today to manufacture a car? Did the number of jobs between then and now shrink by that factor? To the contrary. The car industry had an incredible boom.
Efficiency increase does not imply job loss since the market size is not static. If cost is reduced then things are suddenly viable which weren't before and market size can explode. In the end you can end up with more jobs. Not always, obviously, but there are more examples than you can count which show that.