If it provides a competitive advantage for fathers to sell their labor to not take parental leave, then they won’t. In that case, if the government wanted to incentivize fathers to take parental leave, they would have to mandate it, but of course that would conflict with goals of providing freedoms.

It’s the age old conundrum of what is good for society versus the individual, and how an immeasurable benefit (fathers spending time with children) can lose out to measurable benefits (fathers being able to sell their labor for a higher price due to having more experience/getting promoted since they didn’t take parental leave).

The other benefit of forcing fathers to take parental leave, would be to help equalize the playing field for men and women. But then the country may lose a competitive advantage to other countries since their products might be cheaper since they have a greater supply of labor, but in the long term it would be beneficial for the world to have mothers and fathers both spend time rearing children, however it unquantifiable unlike their cheaper products resulting in higher exports.

The key issue with paid leave is...paid by whom?

If its not paid by the parents, who is paying for it? It often is a mix of co-workers, consumers, and taxpayers.

What society is and can be changed is one thing, what you do by making that society ilegal is another one.