That cost needs to be higher than not breaking the law.

Otherwise, why would a company ever respect the law?

You hire any fresh grad accountant, have them figure out that:

Profit from breaking law > cost of fine

and the company will rationally decide to just keep breaking the law.

That's not a deterrent, it's just another line item in an accounting spreadsheet.

Perhaps because they're not profit focussed. When people becry the evils of capitalism, this attitude is what they're talking about: that it is ok and expected to do the thing that maximises profit and that if we want people to not do something then we need to make it financially uninviting.

It is not possible to arrange the world so that the financial incentives are always aligned with what is the right thing to do. So if we want to "have nice things" and live in the sort of world that most people will want to live in then we need to have some kind of ethical system which guides our action independently of the profit motive.

This seems to be one of the bigger cultural differences between the US and Europe. In the US the attitude seems to be "if there's some situation you can exploit and it's not illegal then why would you not do so". In Europe there is much more emphasis on societal-level reciprocity: not just "will there be negative consequences to me if I do this", but "will this lead to the sort of society I want to live in if everybody does this". Of course there are still bad actors. There will always be bad actors. But the assumption is that most people won't be, rather than that most people will be.

So you're basically saying social pressure? That doesn't work in most cases.

It only really works when people die.

It works in lots of countries, even in the US. Just not in US business culture.