@tsarstepan,
I'm of two minds about this.
With every year and every generation, we improve overall health and longevity when it comes to lifestyle (not talking about viruses, superbugs, etc.). Fewer people smoke. More people exercise. We are a lot more likely to wear sunscreen. We also have a spiraling obesity problem.
So, it's not all awesome.
I am 61 years old and I am still working. I intend to work another 11 or 12 years or so. Some of this is economic, but it's also because I genuinely want to engage my mind. Since I write for a living, I can go longer in my profession than a lot of other people can.
I do bike riding or walking most days, weight lifting most days. No memory or cognitive issues out of the ordinary.
Yet a lot of people would count me out already.
The employment scene is rife with age discrimination.
I hate that the electoral process is another avenue for age discrimination. This treats a lot of people unfairly, and it minimizes experience and wisdom. I'm not ready for a rest home, and a lot of people a quarter of a century older than me aren't, either.
Yet we also cannot discount that there is a cognitive decline and impairment for a lot of people. But we also need to remember that folks can get Alzheimer's in their 40s. Putting some cutoff at, say, age 75 doesn't do diddly about that.
It may be time for certain tests for the presidency. For everyone, regardless of age or party. You get on the ballot anywhere in the US and its territories, then you've got to pass such and such test. Throw in requiring your tax returns for the past 5 years while we're at it.
I'm not talking about cognitive testing like man-woman-camera-whatever. I mean an actual civics test. E.g. what does the 19th Amendment cover? Which branch of government holds the purse strings? What does cloture mean?
Does this knock out outsiders? Not necessarily. Anyone can study for a test. Is it constitutional? I think it could pass scrutiny if it was universally administered. Being 35 years old and running shouldn't exempt someone from the test.
I doubt it would come to pass. But I can always hope.