Biden is NOT too old. Just has partial dementia from not exercising regularly.
I am 82, and last weekend I created a computer program to analize my stock holdings in 3 different outfits, and recomend which accounts need adjustment to maintain my desired stocks/cash ratio. My mind is as good as it was at age 41. OK, the memory is not as good but if I can write a 250 lines of computer code, the mind is still working.
My secret is mild exercise every other day in gym with treadmill and light weight lifting.
Proving my previously stated point beautifully!
I have this theory that you lose about 3% of intellectual ability per decade after 30. So if you start way above average, you can still be plenty sharp in your 80’s, provided you don’t have a real health issue.