The Great Depression of the 1930s saw more American unmarried women working from nine to five, mostly in repetitive, boring, subordinate, dead-end jobs. But the number of working women doubled between 1870 and 1940. During World War II it doubled once again.
You don't come home from the office to spend time with another job. Hopefully you come home to someone you can have a good time with.
If two very different people pool their DNA, they'll create more genetic variety, and their young will come to the job of parenting with a wider array of skills.
We spend our lives trying to get along with people so we can keep our jobs, keep our marriages together, so that we can raise our kids properly.
Women's worst invention was the plow. With the beginning of plow agriculture, men's roles became extremely powerful. Women lost their ancient jobs as collectors.