I don't see anything surprising or "unnatural"! If you are not paralyzed and are not completely incapacitated, there will always be an opportunity to either learn something new, or apply the previously accumulated experience to something. Of course, you should not try to become a povermen at 95, or an astronaut at 100 - there simply physiological limitations will become an obstacle, but intelligence can be used at virtually any age and in any condition!
Yes, of course, this is quite a logical thought in determining the percentage of success in old age by trying new things because the body is no longer as strong and not as fit as when you were young, you also have to pay attention to this, the mindset of age is not a very good reason to grow motivation and enthusiasm, but in this context, look at those who have the abilities they built from a young age and apply them to old age. The likelihood of success will be greater than starting something new at a young age or the consistency of a hobby, such as painting from a young age, which is increasing until old age.
In my opinion intelligence is also built from the many experiences of thinking at a young age and if in old age memory and understanding can be used properly I think that is great but as we know that in old age memory will decrease as well as accompanied by conditions weaker physically.