But besides the fact that the cost of labor has not gone down with women in the workforce, if you look at what kind of work women go into you'll see that with a few exceptions, when it comes to actual labor the supply of potential employees does not go up. Jobs like construction, welding, concrete cutting, mining, smelting, or any number of similar blue collar professions, are predominantly done by men.
If you look at the kinds of jobs that women are taking, barring medicine and education, you'll notice that they are almost all in regulatory roles. They work in the DMV, human resource departments, and in law. So the entrance of women into the workforce has not brought down the cost of labor, it has brought down the cost of regulation.