Except many companies respond to the cookie law with a cookie consent popup that violates the law (by making opt-out harder than opt-in).

Could we really have predicted from the "Law of Unintended Consequences" that companies would respond not by tracking less nor by giving people an easy way to opt out, but with a cookie consent popup that is not compliant and also really annoying to their visitors?

This is better explained by business operators being ignorant of the actual law and being ignorant of the UX impact.