For most occupations with accreditation standards, I’m dubious that practitioners can’t establish reputations in the normal way. In fact, I suspect that many have to anyhow – even if you have your medical practitioners’ certificate or whatever, most of your reputation building will be an ongoing practice based on satisfying your customers.

I do not think that the market for doctors would break down altogether as long as there are still laws protecting you from false claims (e.g. nurses actually pretending to be doctors). If your organization considers that your accreditation is a valuable signal to potential customers, why should you be worried about competitors who have to go without your accreditation (as long as customers can distinguish between accredited and unaccredited)?

The use of cheaper medical technicians to reduce the use of more qualified doctors, as described in the Economist post, probably is the future of medicine. It just seems silly to have extremely qualified and hence expensive doctors seeing every patient instead of utilizing more of a triage system.