Let's apply the same logic to people then. "John scammed his neighbour of his life savings, we don't need to lock him up because lots of people will refuse to associate with him or supply him with goods and services."
Making loss of business or minor fines the only mechanism for correcting behaviour, means that the leaders can view antisocial and unethical behaviour as a cost benefit tradeoff. And the lack of personal accountability means the company leadership has very limited downside, even if they completely screw up.
Crimes of moral turpitude (e.g. fraud), and even some lesser civil acts, are sometimes punished by denying the convicted person the right to have an executive job for a period of years.
Making loss of business or minor fines the only mechanism for correcting behaviour, means that the leaders can view antisocial and unethical behaviour as a cost benefit tradeoff. And the lack of personal accountability means the company leadership has very limited downside, even if they completely screw up.