I do not believe that licensing is the answer, and I have a different opinion on some of your stated points. If licenses were the answers to all problems, we would not have bad apples in any of the professions where licenses exist.
I do not believe that “any idiot can pass a test”; but maybe this is self-serving as I have passed several tests and really do not think of myself as an idiot.
Higher standards: they already exist. There are several certifications, notably ACSM but also others, that apply a very high standard, and some even require degrees.
I see nothing wrong with an entry level into the industry. That is how I started years ago. Whether you ultimately make it depends on your willingness to continue to learn and grow. All organizations require a re-certification, and thanks to this website here, a consumer can see the status of a trainer or instructor.