Whereas previous economic shocks such as the oil crisis of 1973 caused a temporary dip in fertility, the 2007-2008 banking meltdown was different because birth rates continued to decline even after the economy started growing again, says to Daniele Vignoli, professor of demography at the University of Florence in Italy. He believes the turbulence a decade and a half ago marks the point at which people’s uncertainty about the future began to take hold.
That is true, we could be doing a lot to provide a better starting point for our following generation besides just making them a bigger generation.
But I also agree with you here, so I resorted to argue for a somewhat realistic scenario.
Also it does not contradict my point of it being better to spread out your own weight on more shoulders, rather than few. That would still be valid if we did change our productivity towards more socially beneficial projects.