There is this thing called money, that iff you're able to save it, can enable one to do many things - take leave for a newborn, work less longer term to spend consistent time with a growing child, bootstrap a business, explore a completely different field, and many other innumerable things that can matter to a person but don't necessarily fit into top-down policy.

So the real question is why are people unable to just rely on saved wealth to take whatever leave they would like? And the answer is that the financialization of everything has left most everyone essentially living paycheck to paycheck - even the upper middle class! Yet we continue to be distracted by feel good narratives proposing to throw a bone to one popular group or another, rather than pushing to directly reform the economy away from being a treadmill for "full time" work.

It's not a foregone conclusion that things have to be this way. The present conditions are explicit government policy - any time anything would give individuals more economic power (eg technology, productivity increases, women entering the workforce, offshoring, etc), prices are deliberately increased by printing enough new money to erode any gains! It's no secret why "the rent is too damn high", it's just politically inconvenient to bring it up.

An anecdotal argument like this is generally unconvincing. I have a myriad of personal problems, but I can't go to a senator and say "America needs a solution to <the problem I had>", no matter how many other people have had the same problem. Where the latter fact becomes real leverage is in the data - but without the data my argument would not amount to much more than whining. Furthermore, the data needs to prove not that such leave prevents personal distress, but that it's good for America's bottom line. Unfortunately for fathers, the objective fact might be that such leave is worse for the bottom line. There's a reason workaholic cultures like Japan's bring about economic miracles, albeit along with a plethora of social issues. Economics is a huge focus of policies, for better or for worse.

Obviously having parents leave a company for any length of time is bad for the "bottom line". This is an objective fact, because the company must fill in the role somehow and wait for an amount of time before that person, who will be guaranteed their job when they return, can work again (assuming that the way it would work now is extended to fathers, where the job is guaranteed). If the government also subsidizes the family then it also costs the government money as well, which also affects the "bottom line".

However there have been numerous psychological studies that look at the outcome of the baby and the parents when allowed to take m/paternity leave and it's hugely beneficial for all involved. So if you look solely at money then the argument for family leave is "don't do it" but money is not the only important thing when looking at topics like this.

The studies I've seen showed correlative links between m/paternity leave itself with improved psychological results, not necessarily ones that are specific to reproductive rather than personal leave or aren't also tied to the workplace/society having better social support. Somebody with an employer or in a society that allows people X weeks/months off for personal reasons -- whether it's a matter of choosing to reproduce, finish a degree, caring for an ailing loved one/pet, or combating burnout -- is likely to fare much better psychologically than somebody required to work continuously regardless of their personal circumstances.

An interesting parallel occurred a while back when there was sudden widespread adoption of Finland's "baby box" of supplies for new parents after the BBC noticed that Finland's infant mortality rate plummeted after their introduction. The results have been lackluster, however, because people had overlooked that the improvement in Finland had been tied to a whole bunch of policies & healthcare changes, with the box being only a tiny part of the result.

It's more that we need people to live in such a way that they're not paycheck to paycheck.

If everyone spends up to their limit on rent/food/cars/etc then you end up with whole swathes of individuals who "need" concessions from their employer because they have no leverage.

It's not solely an individual decision, of course, because if other people outbid you for housing then your choices can be limited.

The American model seems to be that most people just work for 40 years with a few weeks off per year and that's their entire adult life.

The above is completely stark raving bonkers to me. Economic cogs.