All of these people were professionals. None of them were experts. Get your education from professionals, and always avoid experts. An expert is somebody with a degree. Therefore, in an expert system, the talented, the challenging and the brash are weeded out, and the inoffensive mediocre remain.
Many college professors are experts.
A professional is someone who makes a living working in the field in question. A professional architect designs and builds houses for clients. A professional hairdresser cuts and styles hair for clients. A professional writer writes stories, articles, or books for readers. All of these people get paid by the people who are direct consumers of their work.