I'm autistic - not diagnosed until I was 60. Looking back, I'm pretty sure sure my mother was, perhaps my father and my maternal grandmother.
People masked - I know that mine means that I tend to deal better when there are rules to follow - my upbringing was quite strict, in a loving way, so I always knew what was expected of me, and I went to boarding school before I was eleven, so again there were a lot of rules and I knew what was expected of me. I brought my children up in the way I thought I was expected to.
My mother always did her duty, in that she did what she was expected to do - in bringing up her children, and at work, and socially. I remember her having dinner parties and doing everything very nicely, behaving impeccably, but she never seemed to enjoy them. When there are higher expectations and more rules, it is easier to understand what you need to do. It doesn't make life any more enjoyable, but it is easier to navigate.
Anyone that wasn't able to fit into the 'rules' was labelled as naughty/bad, weird, or mentally unstable. Not autistic.
Nowadays children are given much more freedom to express themselves, to choose what they will and won't eat, there are fewer rules and less of a defined social structure to live within. It is confusing. A child that wouldn't eat what they were given either became malnourished, died, or ended up being forced to eat and developed other issues. That was bad, obviously, but I do think that some children are being given too much choice when it comes to food and other things, it can make things harder, not easier.
And finally - yes I do think that diagnoses are being made more frequently, and earlier, plus it is also being recognised in adults where it just would have been thought of as weird behaviour before, but I also think that more children are on the autistic spectrum than before, perhaps because there is a genetic element and more adults survived childhood to carry on the gene for it.