What makes this issue tricky is that some people are sharp at 75, and that continues clear into their upper 80's.
Other people start slipping at 75
Others are fine at 75, but then start rapidly slipping over the subsequent 5 years.
Given the stats on the percentage of elderly people it happens to, I think it's time for the country to have a conversation about an upper age limit to compliment the lower age limit we have in place.
Some may view that as "ageist", but for certain key positions, it's pragmatic for elevated age to be a consideration.
When hiring someone for a 4-year position:
Learn about the average life expectancy in the US, and your odds of dying within the next 5, 10, 20 or 30 years based on your age, gender and race.
www.finder.com
If you're 70, you have a 12% chance of dying in the next 5 years.
If you're 80, that jumps to close to a 1/3 chance. By mid-80's, it's a 2/3 chance.
Given the nature and tenure of the position, those odds, combined with the 40% chance of people in their mid-upper 70's developing cognitive decline in the next 5 years, I think makes a pretty strong case for setting an upper limit of 70.
To put that in perspective, such a rule would've only impacted 2 presidents: Donald Trump and Joe Biden. Literally every other president has been under 70 when they took office. (In fact, after Biden's time as president, that'll make only 4 who've even been over 70 when leaving office)