Daycare and what does work pay for?

This is Joseph

So, I have a philosophical question. It is clear that work places benefit from having a robust set of benefits for workers, many of which make a lot more sense given as a employer benefit rather than as a part of cash compensation. In the United States, for example, the current regulatory system favors employer sponsored health care (although I hear they are in the process of revisiting this assumption).

Other benefits are a lot more standard. For example, heating and/or air conditioning makes a big difference in an office. Parking is another case where you could just give employees money but liquidity issues might make that inefficient (is there a private parking vendor near work that employees could rent spots from? Will land use allow this?).

An interesting case in this rubric is daycare. On site daycare would make at least as much of a positive difference for workers as on-site parking. Not everyone uses parking and not everyone uses daycare, either, but it would be a broadly useful benefit. It is also quite possible to offer paid daycare just like many universities offer paid parking.

My question is what is it that has kept daycare from being in the same category as parking for workplace infrastructure? Marissa Mayer was famous for thinking that raising a child as CEO wasn't as bad as people predicted, but she had a daycare in the office next door. Now, she paid for the expenses but the typical employee does not have the option to pay for a daycare in the same building, even if they want to.

Is there a reason that this relatively big boost in workforce benefit is so rarely fully staffed? Most daycares I am looking at, in multiple cities, have difficult wait lists and are hard to coordinate with work locations. Can't this be improved?