I would point out that for many people the cost of paying for childcare during work hours is comparable to the income generated from said work. Those people have essentially no incentive to work unless they want to avoid their kids.
Even if it's a wash dollar wise, staying employed often means you get healthcare and retirement benefits AND the career progression that ideally comes with long term stable employment. Trying to hop back on the treadmill after a 5-10 year absence often has a huge opportunity cost on your lifetime earnings.