I read your link and it quoted findings from one (1) doctor.
The Le Leche League formed in 1956 and had one year in 1957 where it declined, but resurged in the 1960’s and 1970’s
http://www.faqs.org/nutrition/Ar-Bu/Breastfeeding.html
From your link: “Breastfeeding rates began rising again in the late 1950s and early 1960s.”
I agree. It came back into vogue and numbers “began rising again” about the time Barry 0 hatched.
Your family was apparently part of the resurgence.
But breastfeeding didn’t again gain wide acceptance until the back-to-nature movement in the late 60s, early 70s. Earth mothers and all that.
My post, like yours, was from personal experience. My family and our friends.