My dad was 40 when I was born. He was literally old enough to be my grandfather and he was, in fact, a year younger than my ex husband's paternal grandmother. My ex and I are the same age and graduated high school together.
My dad grew up on a farm. He lived for a time in a log cabin with a dirt floor.
When I moved home with my two teenaged sons during my divorce, my parents' house was much quieter than we were used to. My parents expected things to be quiet at night so they could sleep. No, they weren't going to buy a white noise machine or something.
No one ever suggested my parents had sensory issues or anything like that. They were merely old and grew up in quieter circumstances and no one acted like their expectations were maladapted or pathological or something.
I've arranged my life to be a lot quieter than it used to be. My sons are much more able to function "normally" now that our lives are quieter. I sometimes forget how poorly they handle noise and crowds because we are so rarely in such situations. Then we go to a restaurant or something and they can't deal and I'm reminded again of just how difficult they can be.
I have come to believe that the world has changed and human children weren't designed for the busy, noisy, crowded world full of sensory overload that is our new norm. But instead of recognizing that the world has changed, we label children as defective who don't deal well with this noisy, crowded, busy, crazy world that didn't exist when my father was growing up less than a hundred years ago when most people lived and worked on farms.
It is in the lifetimes of my children that this statistic changed and now most people live in cities. But that's very new. For the vast majority of the history of the human race, we were mostly tribal or agrarian. City dwellers were the exception, not the rule.