This isn't true. The current birth rate crisis is artificially induced by the widespread production and use of birth control pills.[0] If you look at the fertility rate graph, it fell off a cliff from 1960-1975 when the pill was introduced and has remained relatively stable ever since.[1] America's fertility rate would be well above replacement if we never invented the pill.

Popular socioeconomic explanations for why people are having fewer children aren't wrong, but those aren't the biggest factors. They likely explain the drop from 2008-present, but this recent drop is nothing compared to the 1960-1975 pill cliff. If you claim the socioeconomic problems are unsolvable (which I don't think is true either), there is still the option of regulating the pill as a controlled substance.

[0] https://en.wikipedia.org/wiki/Combined_oral_contraceptive_pi...

[1] https://www.macrotrends.net/global-metrics/countries/usa/uni...