In this well-researched and well-written article at Reason magazine, the primary focus is on what has caused the fertility decline. It pinpoints no single factor, and says that all of the known factors combined still do not explain the dramatic drops in children being born. It suggests that everything matters, plus there may be lag involved, plus a whole lot of women are simply less interested in being Mums, regardless of reasons.

In the section regarding incentives, it does a great job summarizing things that have not made much difference:

  • Countries from Russia to Japan to Italy have tried an array of measures—from pressure campaigns to subsidized child care to giving people days off work for making babies—to raise national birthrates. Yet fertility rates remain stable or continue to fall.
  • South Korea spent more than $200 billion subsidizing child care and parental leave over the past 16 years, President Yoon Suk Yeol said last fall. Yet the fertility rate fell from 1.1 in 2006 to 0.81 in 2021.
  • The Japanese government almost quadrupled spending on families between 1990 and 2015, expanding child care provisions, paid family leave, parental tax credits, and more. The fertility rate went from 1.54 in 1990 to 1.3 in 2005 before rebounding slightly (1.4 in 2015) and then falling back to around 1.3.
  • And then there’s Singapore, which offers $8,000 for a first or second baby and $10,000 for every child thereafter—up from $6,000 and $8,000 back in 2014. The authorities have also tried offering tax rebates, guaranteeing 16 weeks of government-paid maternity leave for married mothers, giving housing subsidies to parents, matching Child Development Account savings up to thousands of dollars, and other schemes. None of this has stanched Singapore’s plunging fertility rate. In 1990, it was 1.83. In recent years, it has hovered between 1.1 and 1.2.
  • researchers found “one extra percentage point of GDP spending” on early childhood education and child care programs was “associated with 0.2 extra children per woman.”