Not OP and anecdata but our CTO is in his 60s and contributes a lot of code to a fairly modern stack, he doesn’t appear to have any trouble keeping up.
Not really sure how to answer that. He's obviously slower than he used to be, but can still do the job.
My father (not a programmer, but an administrative clerk) would say that he's slower but he can instead rely on experience more.
And irrelevant to the conversation unless managers are better protected for cognitive loss (I doubt it) or managers requires less cognitive load (I doubt that too, but you can make a joke about that :)
It's none obvious that various cognitive skills (and the amount of energy/motivations) decline at the same rates and that managing and programming requires the same skills.
I'd love to program until I am in my 70's (if programming still exists) this is why I ask.
WOW, what a question....most probably better then you, when reading your comment.
I generally don't answer to random trolls, but if you want to understand the intention of this question, read my other comments.