Not true. Its the lower income workers who are working almost for free. A second car+gas+insurance+taxes, income taxes, clothes, lunch out, day care for 1-2 children.
These items are pretty much fixed price regardless of your income. These costs don't exist if the wife is at home. These costs can also easily add up to $35,000 per year ($5K for ownership/insurance/gas/taxes on the car, $1K each for clothes and lunch, and $12K for daycare for two, then $16K in income/social security/state/local taxes on that $35K).
Also, it is the lower income worker, not necessarily the female parent, who's income is going to pay for the cost of working in the first place.
Again, not true. There is no "cost of working" for the first worker beyond the basics of transportation to work, work clothing and lunch away from home. Those are the more minimal costs to begin with. Daycare and a rarely used beyond commutation second car are the big ones.
What really drives women working is families desiring huge homes that one worker cannot pay for, multiple pricey cars/trucks, and a desire to spend $2K+ per month on discretionary items, food, and vacations.
In most of the country, a man earning $40,000 per year should be enough to afford a $100K house, a single family car, and a wife at home with the children. People who want more than this, and do not earn enough to support it, are the ones driving the women working kids in daycare phenomena.
Materialism has indeed been a factor in driving both parents increasingly away from their children and their parental responsibilities. To their shame they choose things over the welfare of their children. What a tragedy.
I at one time was guilty of the same. But by the grace of God I have realized my transgression and have made amends. A parent's duty to his children is sacred.