They did not have "plenty". The average boomer put off having kids until the woman was 30; they were the first to use birth control; they were the first to use wide-spread legal in-vitro child-sacrifice.
If they had done nothing more than maintain, during the easiest, wealthiest, most luxurious, least hungry period of time in all of human history, we would see that graph showing a flat line.
Line go down.
