My understanding is that, for example, there are places where the surface soil was 5% lead (like on the sides of busy roads) so the amount of lead was significant.
So why did children in particular not develop signs like blue lines in their gums? And why was leaded paint considered (I think) a greater danger than leaded gasoline?
EDIT: One thought is, blue line in gums as I now understand it is not from systemic lead poisoning but from the action of bacteria on lead in the mouth. So eating lead paint or drinking from lead-glazed cups can cause this symptom; breathing fine particulate lead would not. (But eating contaminated soil might cause it.)
However, there are other acute lead poisoning symptoms that could have been seen. I don't know, maybe they were and were attributed to paint when in fact they came from gasoline or a combination of the two. There was also lead in newsprint (colored and kids who used Silly Putty to capture funny pages images and subsequently chewed on the Putty could have gotten lead exposure that way) -- let's face it, there was a lot of lead around and the powerful fossil fuel industry as well as the equally powerful car manufacturing industry plus the makers of the gasoline additive definitely fought for tetra-ethyl lead and would have argued that acute lead poisoning cases came from other kinds of exposure than car exhaust.
What a frigging tragedy that billions of people were exposed to lead unnecessarily for so many decades.