The credentials you mention fall into three kinds:
1. Credentials Legally Required: Lawyers, Doctors, etc.
Credentials and accredited schooling are required in these disciplines because they involve specialized knowledge AND because misuse or malpractice can seriously hurt people. Even then, there's plenty of cartel-like behavior going on. For example, the U.S. system of accrediting lawyers (three years of graduate school plus bar exam) is almost certainly overkill.
2. Specialized Technical Skills: Welders, Trades
Welding, fabricating, etc. require specialized skills and knowledge. These skills are taught in trade schools and through apprenticeships, not four-year colleges. The credentials are usually not LEGALLY required to work in the area - you can hire a welder who doesn't have one - but in practice, you want to hire people with the credentials because they probably know what they're doing.
3. Non-Technical Skills: Teachers, Social Workers
Teachers, child services workers, etc. Here I think the argument for credentials is the weakest. Why do we NEED accredited teachers? For centuries we've had teachers who never had one, and even now, many private schools don't require credentials. In fact, some of the best teachers I had in school never had teaching degrees - they had degrees and experience in the relevant field (say, chemistry) and came to teach. In fact, in some of these fields, the credentials are attempts to form bars to entry, thus protecting the existing members of the profession - just why do we need school + certificates for hair dressers?
So where does software engineering fall? I think the second category is where it belongs, and bootcamps are attempts to create the kind of technical training / apprenticeship that exists in the trades. That doesn't mean official CS degrees are worthless - far from it - but it also means that we don't need any bars to entry for people who decided to learn coding in another way.