We are well out of the baby boom of WWII so there is a giant slow down of folks having more than two children let alone more, like it was when I was a kid. Only a certain amount of kids and young people in general have an interest in mechanical things like we did. The only way that boom would ever come back to get even close to the boom numbers would be another survivable calamity like the previous wars. Folks were used to having children at home with a midwife or experienced relatives back then but not any more. Hospitals and OB/GYN doctors charge a fortune and a lot of feminism has resulted in a very low percentage of young women wanting to have more than one or two children so they can have a career too. What was conventional in 1919 or 1945 has completely changed in the modern era.
Three assumptions in this post are false:
1. Assuming that the war caused the baby boom
2. Assuming that baby boom families tended to be large
3. Assuming that baby boom mothers mostly gave birth at home
First, there's no evidence that the baby boom of 1940-1960 was caused by the war. No other war of the 20th century led to an increase in fertility rates. The increase was global and unrelated to a country's involvement in the war (birth rates spiked in Austria, for example).
Second, it's not true that baby boom families tended to be large. The number of families with more than three children actually decreased during the baby boom. What is true is that (1) women married more often and younger, and (2) women were more likely to have either 1 or 2 children than to have none.
In 1930, 54% of US women aged 20-24 were married; in 1960 it was 72%. The average age of marriage dropped from 22 in 1940 to 20.7 in 1955. The percentage of married women who had at least one kid rose from 77% before the war to 92% after it.
Third, it's not true that "Folks were used to having children at home." In 1940, only half of births took place at home. By 1955, the height of the boom, 99% of deliveries happened in a hospital. The great majority of boomers were born in hospitals, not at home surrounded by "experienced relatives."