I did a quick google search and found this article. It seems like it is a conservative news source, so I am skeptical of the bent - but the facts seem to support my view:

Israeli Jewish parents and particularly mothers deserve recognition. Raising children requires sacrifice, patience, and devotion. These mothers achieve this with just 14 weeks of paid maternity leave per child—less than the OECD average of 19 weeks and far less than many European nations. Israeli mothers return to work earlier yet still have more children.

This growth comes overwhelmingly from those closest to Jewish traditional values. Haredi families lead with an average of over six children. Religious families have nearly four, and traditional Jews exceed the replacement rate with almost three children, while secular Israelis fall short with just two children. Those who preserve tradition are building the future.

The narrative I see here is that Israel has moderate support for families, and the reversal of birth rates is being driven by religious conservatives responding to a call to outcompete Palestinian birth rates. I'm open to other interpretations of the phenomenon from other sources, or your own interpretation of the article - but I feel like this matches up with my prior assumptions.

The driving force in low birth rates is emancipation and secularization of women. Providing more maternity leave, more child-rearing stipends, better health care, etc, simply won't sway women who take a rational look at the process of birthing and raising children - destroying your body to be chained to a thankless responsibility for 18 years - and decide that they would rather have more money and free time instead. I will say my personal opinion on this descision is "that makes a lot of sense to me, good for you, snowboarding does sound a lot more fun than trying to control a child's temper tantrum in a starbucks." Of course, there are people on the margins, who would have a child if their economic conditions were better - but my feeling here is that this is a moving target. What counts as "ready" has less to do with actual physical needs, and more to do with being able to essentially keep up with the Joneses. Ie, the prospective secular mother wrings her hands, worrying that if her child can't get into an Ivy League college then they will be miserable and so what is the point of giving them life in the first place? The religious mother, on the other hand, has absolute clarity (as reinforced weekly at her religious services) that motherhood is the greatest honor and responsibility she will have in her life, and that every life she gives birth to is a fantastic gift, regardless of how miserable it might be, and so gives birth while deeply in debt and living in a trailer park.