I think you're correct at a low-level, but reducing an entire person's thought process on the long term to a single focus? That is extremist. In any sufficiently complex system or company, you will have multiple inputs driving multiple results. You will be dealing with multiple people. Your work will touch the work of others. This may work in an extremely rigid, top-down authoritative structure, but personally I don't believe extremely rigid top-down authoritative structures are effective. Your opinions may differ from mine, but I think autonomy, mastery, and common purpose are far, far more powerful tools.