Fake cures, filthy mines, toxic ingredients, polluted waterways, fraud, predation, monopolies, algorithmic social outrage networks, etc. These things have been going on for a long time. Regulations have fixed a lot of problems.
It doesn't seem that reputation matters as much as regulation. It doesn't take many greedy people/companies to leave behind a big mess. Just a few breaking the rules (including the cultural rules around reputation) gain an advantage over all those who don't.
What better way for society to protect itself?
The point was, increasing shareholder value is equivalent to increasing their own paychecks. So they are doubly incentivized to choose shareholder value over other values. Most people would still choose health/life of other humans, but the incentives are certainly off without regulation.