It's not an exaggeration, OP meant in the context of a knowledge economy. the IQ and crime issues you mention strongly support this statement.

Without commenting on how likely it is the hypothesis is true, the lead-crime hypothesis has always been academic handwaving to make a different, political point.

And for some reason we thrived poisoned and are failing lead free....

Arguably we're now seeing the political system controlled by geriatrics that grew up in the leaded fuel era.

No, we see the consequences that it causes in young people: The loss of sense of priority, the loss of capacity for independent discovery and the judment of reasonableness, the disruption of normal thinking (leading to making things up, to outright paranoia and psychosis).

Ok boomer.

In the pre leaded gas era, there were cane beatings on the floor of Congress!