You're computing the value of a parent's career as a single point in time salary value, and not as a integration under the curve of salary earned over time. A p

You're computing the value of a parent's career as a single point in time salary value, and not as a integration under the curve of salary earned over time. A parent may not have the cash reserves at that single point in time to pay for childcare out of pocket, that doesn't mean that the value they get from staying employed over time does not exceed that cost. Leaving the workforce starts you over at zero. Universal childcare, especially in the earliest stages of life, provides societal externalities that vastly outweigh the cost of providing it. It ought to be a public good.