In reality, a single earner household is actually relatively new - post world war 2 as the Bush was to make way for returning soldiers and repopulate. The jobs women did were more in the home (wash their and others clothes, prep food for more than just family), and the outside the home jobs were teachers, nurses, caretakers, etc. (Hence why many of these jobs pay lower still today regardless of gender).

But now, two earners can meet the demand for more stuff and to keep up with rising prices, partially caused by? Two-worker households