This is the argument I've been making for years. I used to be _way_ smarter than I am, I have concrete examples of things I used to do with ease that are now major cognitive effort, but I'm still alright in a lot of ways. Most folks meeting me would still consider me pretty smart, although I have profound struggles with memory lately.

And there doesn't seem to be a doctor in the world who considers this a problem. "Yep, it goes 0-60 in 27 seconds, just like a chevette should!" "but doc, it's a bugatti". That would be one hell of an incompetent mechanic.