I mean, Midgley knew lead was dangerous. He suffered from lead poisoning himself. People in his plants died and came down with serious lead poisoning just a year after he had to step away because of his lead poisoning. He was directly informed about the risks of lead years in advance.

Two years after he got lead poisoning, he did a demonstration where he huffed TEL and poured it on his hands and claimed he could do it every day without consequence. Nobody believed him, perhaps because it was no secret that lead exposure was dangerous. The state of New Jersey didn't believe it either and shut down his plant, and he later came down with lead poisoning again and had to take a leave of absence.

So to your point, these were the actions of a man who saw people in his factories dying, came down with lead poisoning twice himself, and kept selling the stuff. That's not a lack of foresight, that's just greed. He just didn't care. The benefits he saw were "making a shitload of money".