His point was the government could certify that their skills met a specified criteria, but people would still be able to use the services of a practitioner that is not certified. It would come down to the choice of the consumer if they felt that the government certification was worth anything.
In some occupations that might be OK, but I don’t understand how that would work in occupations where there is a public interest in ensuring the competency of the people who are involved. If someone is going to build a 25-story building in your neighborhood, I think everyone can agree that there’s a legitimate interest in having it designed and constructed by licensed professionals.