> real boom after all is the cohort born around 1960.
There is a boom in birth rates which remains sustained high for about 10 years. However, the conditions of early childhood environment keep improving along with a reduction the hazard of early death. The 1945 cohort does end up being hit by the Vietnam war whereas people born in the 60s do not face any of that.
Going [1]->[2]->[3] shows that the real boom after all is the cohort born around 1960.