They are supposed to, but often times they don't and there are no consequences for it.

Current diagnostic setup relies on humans having vast expert knowledge, when in fact it's almost always impossible.

A well trained neural net/LLM will always be better at visual detection because of sheer number of examples it sees during training, compared to a dermatologist which, if lucky will observe no more than 20 patients/day x 270 days a year x 40 years of practice i.e. around 220k samples throughout his lifetime.

MD with other specialties will see significantly less and we are talking about top of the top specialists.

An average MD knows more amount medical diagnostics than than the average Joe, but in principle much less than a well trained AI.

Do we have those kinds of models already? Maybe not yet but, ceteris paribus, we will definitely have them in the future.

IMHO we do have those models already but they aren't available to the public, though their availability would certainly lower cost for healthcare providers.