I mean, the brain layer is a metaphor of course, there won't be a dedicated AI area because evolution is not going to select for AI capability over tens of thousands of years.
But I agree that, like any new tool, there's going to be an inflection point where AI starts to become the most efficient method for certain tasks, use of AI becomes a skill that our brains start to treat as a body extension, and there will be a (mostly generational) adaptation moment where some people's brains are no longer plastic enough to adapt.
I think that intuitive expectation - that we may not be able to compete in our lives/jobs while others do more with less - is a large source of our collective anxiety.