What does it take for someone's skills not to be a commodity? I imagine sports starts, rock stars, famous lawyers, and so on, but they come and go. There are

What does it take for someone's skills not to be a commodity? I imagine sports starts, rock stars, famous lawyers, and so on, but they come and go. There are also people so specialised and knowledgeable; physicists, mathematicians, and other scientists, etc. It's all a case of 'degree of commoditisation', I think, but one of the few non-commodity 'skills' is probably personal connections.