Fortunately all of history exists and we can look at the fact that where regulation wasn't imposed and see that the majority who were most willing to foist high external costs on society were able to out compete any minority that behaved more admirably and most markets tend to end up dominated by a few players nearly exclusively from the less ethical fellows as even a small initial advantage is magnified because higher profits in one cycle provide a successively higher advantage in future cycles. Economists have been explaining why this is for literally centuries. Markets don't handle externalities without external regulation. Despite centuries of examples we still have folks asking for "self regulation" which we know doesn't work.

Companies have and will kill thousands of people to have slightly more money.