is it not reasonable to ask (a) what is neurotypical and where does it become neurodivergence? and (b) why are there so many more people now who either have more difficulty with the world than people in previous generations did, or have more severe levels of need?
a) That's what we have diagnostic criteria for, assessed with instruments like ADOS.
b) The world is brighter, louder, and generally shittier for autistic people than it was. People who used to cope now can't. In the last decade, advertising billboards with paper stuck to them have been replaced with backlit moving computer displays everywhere. You go to a bus stop, the advert moves and changes where it previously stayed still. Shops play music interspersed with adverts, frequently loudly as at branches of River Island. You use a website, there's adverts all over websites, moving and covering the screen. Forty years ago, people didn't have the internet at work, many didn't have computers at work. Thirty years ago, home internet was in its infancy. People add noise to public places by using phones without headsets to watch videos and listen to music, a development of the last twenty years. Making calls in public didn't happen thirty years ago.