Falling fertility rates in general seem to be a fairly natural result of societies progressing through agrarian to industrial to post-industrial phases. As countries get richer and better educated and see their infant mortality rates fall, folks seem to tend to have fewer children and have them later in life. People complete their educations, get their careers started and their finances in order, and then very deliberately have a smaller number of children than in ye olden days. If there's a tradeoff between people completing their educations, making sound financial decisions, and purposefully planning parenthood vs. a higher fertility rate, I'm not sure I'd call the former "wrong." It's the nature of life and the family in the First World.
Nations with more family-friendly policies, e.g., the Scandinavian countries, don't seem to have appreciably higher fertility rates than the U.S., so whatever the merits of such policies that one doesn't seem to unequivocally be one of them.
This is basically true, although the family-friendly policies in these countries actually do have a more significant birth rate boost effect when you dig a bit deeper into the numbers. The only reason the U.S. appeared to have a higher fertility rate in comparison to the Nordics-- despite our family-unfriendly lack of affordable daycare, maternity leave and healthcare in the US-- is that at least for past 20 years, the U.S. has had an immigrant Latino population with a much higher birth rate than any European or European-descended group in the United States. Despite all the headlines about Sweden's integration struggles, its immigrant population is actually quite low esp. compared to the US. The Syrians, Afghans and Somalis have only very temporary status in Sweden and are expected to leave after temporary asylum, and even the comparatively small numbers there have been facing heavy deportation recently (or some just emigrate again to England or to the USA or Australia). In fact almost all of Sweden's immigration has been from other Nordic countries or, more and more lately, from eastern Europe and even the UK for some reason.
So when you separate the population sub-groups in Sweden and do a more apples to apples comparison, ex. between native born Swedes and native born European-descended white Americans, the fertility boost among Swedes from their more pro-family programs becomes more obvious, while the sharp drop in US fertility becomes clearer. It's even more apparent when comparing to Sweden's situation a decade ago, with the family-friendly childcare, maternity leave and general universal healthcare policies having a more pronounced effect. France and most recently, Germany are seeing an even more pronounced impact, with the native populations seeing a birth spike in part thanks to such policies (though it's leveled off in France). Many Americans who move to Sweden, France and Germany, when interviewed, say they've started families there that they couldn't back in the US.
I think that a lot of the birth rate drop from the lack of such family friendly policies in the US, is only now just starting to become apparent, and it'll become more pronounced in coming years. This is partly because the economic pressures on Millennials and Gen Z are becoming much harsher with the costs of student loans, housing and health care going up so much esp. in the urban areas where most jobs are. Meanwhile the echo effect from higher religious observance in previous generations is fading-- the US has had the sharpest drop in it's evangelical Christian and general religious population of any developed country in the past decade. Plus, immigration to the US is also leveling off-- fewer and fewer international students as well as skilled workers esp.-- while more Americans seem to be going abroad. So in practice, we're only now just starting to unmask the effects of lack of good daycare, affordable healthcare and family leave in the US, as the confounding factors of higher religiosity and a much higher fertility immigrant population start to level off.
Although I do agree with you on the broader point. Lower fertility seems to be a function of overall development, education, wealth and urbanization levels. Even the most family friendly policies can only do so much.