When looking at what happened (but not causation) one cultural change in the 1970s (in the US, at least) is that many more women began entering the workforce (f

When looking at what happened (but not causation) one cultural change in the 1970s (in the US, at least) is that many more women began entering the workforce (for multiple reasons). This created a big jump in two-earner families, greatly enlarging the number of potential employees as well as the middle-class. (Another impact, latchkey kids.) Forbes summary: https://www.forbes.com/sites/lisaquast/2011/02/14/causes-and-consequences-of-the-increasing-numbers-of-women-in-the-workforce/#3820d1de728c https://www.forbes.com/sites/lisaquast/2011/02/14/causes-and...