They may have been a dog and pony show but were definitely real and forced executives to change how they hire and promote in illegal, discriminatory ways.
From my perspective, that has not happened. My problem is their lack of teeth to do what they say they do.
This thread also has a lot of anecdotal examples of failure modes of 'diverse slate' rules, though, such as people who have already decided who to hire still interviewing women candidates just to appease the rule, thus wasting everyone's time.