It seems to me that people were never allergic to peanuts until the 1980's. I had a number of allergies as a kid, and went to an allergy doctor, and he gave me a series of diets with and without various foods to determine what I was allergic to. I don't think peanuts were mentioned on any of the materials he gave me. I used to eat PBJ sandwiches nearly every day.
I know wheat gluten was on the list of possible foods to omit, but I don't remember ever being told to not eat peanuts.
Strangely, I do not seem to be allergic to anything, other than some Cholesterol-combating margarine (I think it is called Promise) that gave me a rash. I went away to college in New Mexico, spent a couple of years in Mexico, and when I returned, my allergies had mostly vanished.