> easily able to coach any sheep to do any action

No. This assumption is the core fault with the entire line of reasoning. The typical sheep will not do arbitrary things for a stranger such as sending you his entire bank account because you told him he needed to pay an IRS penalty in crypto to avoid being picked up by the state police who are already en route in 15 minutes.

It's a continuum. The question is how much of the low end needs to be protected by the system.

Binning into discreet blocks to match your example, the question is where to place the dividers between the three categories - nerd, sheep, and incompetent. We don't care to accommodate the third.