You can share your wisdom and be of great value to the public without being in public office.
At some point, though, you’ve gone from useful adult into honored elder, and while I’m not suggesting we put them all on ice floes, they shouldn’t be running the country, especially since more than a few of them clearly don’t even know which country they’re in, let alone how to run it.
If you can’t walk, are having strokes, have developed dementia, and generally just sit around staring at the wall like my cat, perhaps it’s time to gracefully retire and go spend the rest of your life doing conferences and speaking engagements and whatever the hell else you want, not trying to legislate.
I kinda have two responses here, so uh, here’s both of them:
Well, by the time this is an issue, odds are you’ve been a career politician anyway and don’t need another job. This is just old people who refuse to retire because they like the power and trappings more than they care about doing their job.
By the time they MUST retire, these ghouls have stolen sufficient money that it doesn’t matter, and sticking around is just them refusing to give up the power and feed their greed even more.
Both seem equally reasonable and applicable to the problem.