Corporations, like many other organisms, will do what is best for them at any given moment, including deciding whether or not behaving ethically is in their best interests
The US could elect some Bernie Sanders or Jeremy Corbyn like figure who is actually tough on corporations. It could happen! Some measure similar to what the Fed did to Wells Fargo would be unthinkable to people used to this pessimistic political climate, but it's happening now. It wouldn't be hard to get elected on a message of raising corporate taxes and bend the rules however necessary to get them to actually pay.
Edit:...And the death penalty, which I oppose, but has been a constant for thousands of years.
Just because something isn't perfect doesn't mean it's not the best outcome.
If you've got a better idea let's hear it.
Edit: The Chickenshit Club is a good read which relates this in more detail.
I don't think raising that starting figure is going achieve much but maybe it works differently in other countries.