Teaching productivity is not like teaching mathematics or philosophy. There is a limited range of things to learn and apply, and the core ideas are concise but difficult to put in practice. A good teacher in that space would essentially be able to impart their wisdom in maybe two hours, at which point the success of the teaching would lie in the student actually following what they were told. An ongoing productivity podcast or book series flies in the face of this. The mere act of commercializing productivity dooms the entire edifice. If the student is still on episode #23, the sales has succeeded but the teaching has failed.