Disagree somewhat.

A human with no exposure to information and taught techniques on how to produce outputs to achieve desirable outcomes? Yes stupid.

A human who once had this exposure, but no longer engages with the brain due to a machine providing access said output? Yes, that person becomes stupid.

The problem is much of how one protects oneself in the modern world is not phyiscal-prowess, it is intellectual-prowess.

The smart ones have already realised the negative impacts of LLMs et al and are going back to the old-fashioned way of learning/retaining knowledge: books and raw discipline.