Back when deeply ingrained societal ideas were first being forced into the genome it took a wide-range of life experience to survive to an old age. Sure most people that lived to 5 made it to 50 for most of human history, barring pandemics and society-changing ~~genocides~~wars, but most people don't even gray or wrinkle by then in any significant way. But we all know to treat old-looking people with more respect than others; specifically because to make it from 50-whatever before a time of antibiotics and nutritional science required an incredible amount of experience dealing with a lot of people (you could just be left to float out on an iceberg or chucked off a cliff or left in a forest if people don't like you after all) and an incredible amount of folk wisdom on how to get a varied diet in the location you were in so that the common stuff doesn't kill you even when you're vulnerable.

We've abandoned that part of the human and animal experience, but we still hold the genetic memory of the time when that was common, since it was less than a century ago for most of humanity. The old people alive today statistically rarely struggled, they never really had to grow up, and they inadvertently developed a society perfectly focused at keeping old people alive for as long as possible to drain them of all their financial resources. So they have no more wisdom than a 20-something that doomscrolls on the fairly educational side of the internet.