In that regard, it's been a fact since the division of labor was first outlined (and then fetishized) in the late 18th century. In terms of breaking down the tasks needed to build the final product, early Ford factories were just as efficient as modern Foxconn assembly plants.
I'm not arguing whether it's a fact or not. Culturally, in 2015 America it's a fact. In 1915 America, the same "fact" would have been handily rejected, even by conservative minds. Most people only read the first chapter of Wealth of Nations where Adam Smith extolls the virtues of the division of labor. The second half of the book, where he warns that the division of labor taken to the extreme could result in unfathomable social ills, and we ought not ever travel down that path, is usually conveniently ignored.
I'm all for automating jobs that technology deems unnecessary. The solution isn't to push everyone into some multi-disciplinary creative class. Many people would be very happy as uber drivers, or any other menial job, if they were treated with respect by their employer. I'd say the solution begins with treating workers with dignity and respect.