Even in the case of two countries where country A outcompetes country B in productivity at all possible classes of product, it is STILL more efficient to have country B produce a limited number of products and trade them to country A.

This isn't a matter of productivity. It's a matter of efficiency. If a Mind can construct 1000 widgets or 2000 gadgets in a year, and a human can only construct one widget or one gadget, it would be best for the Minds to produce gadgets and the humans to produce widgets, but if a Mind can construct 1000 widgets or 2000 gadgets with one unit of resources, and a human can only construct one widget or one gadget, you're better off just having the Mind make everything.

Even if they're producing thoughts, the humans are made of matter that can be used to make Minds. If nothing else, you can choose between having more humans or Minds. Two Minds can produce 1000 widgets and 2000 gadgets, but a human and a Mind can only produce 501 widgets and 1000 gadgets.