I don't think he's actually arguing it, at least not outside the context of the magic industry. I think it fairly clearly wouldn't make any damn sense in, say,

I don't think he's actually arguing it, at least not outside the context of the magic industry. I think it fairly clearly wouldn't make any damn sense in, say, pharmaceuticals. The only thing that makes the guild system possible is good magic tricks aren't readily reverse-engineered. Also, since the quality of a magic act is more to do with the quality of the magician's showmanship and patter than the quality of his actual tricks, secrets in magic aren't nearly as important as you might think.