Old people (those over 70, I guess) have it all figured out. They have had lots of time to get it all figured out. Since they have it all figured out, they don't want any changes. Nothing should get better since it will interfere with what has already been found to be good, superior even. Nothing should get worse since that too will change rankings, choices, expenses and add to the daily work.
The situation is rather sad, though, since there probably was a moment there when life was all figured out. However, aging set it, research was conducted, new fashions emerged. Some people and some brands changed, you know, from retirements and all. Deaths occured, young people reached maturity and the world would simply not stand still, damn it.
I have read a couple of times that many of the so-called 'senior moments', when an old person can't recall that cousin's wife's name, even though he knows full well that he knows her name and that her name will come to him before Christmas. Maybe we will get additional processes for emptying or partially emptying our brains.
When I search "Real brain actual washing, emptying" I find this:
You use this shortened link to see the results of the search. Turns out that our bodies do wash our brains during sleep.
