I don't agree with this at all. I think the amount has always been constant, it's just that before these modern times, no one had a collective name for it, nor did the vast majority of people work with their intellects, but rather worked as human machines--that is serfs, peasants, farmer workers, etc.
I started using ancxestry.com for my family about ten years ago, and now have done numerous genealogy studies for several others. One thing shines through--every family has had it's criminals, ne'er-do-wells, hermits, unsuccessful uncles, spinsters and others labeled in this manner. I believe they were nothing more than autistic.
No doubt, some of them were autistic. I suspect you have done well and other family members have done likewise. I grew up doing the dirty work on the farm in the Midwest. I sweat so much hauling hay in the summer heat my clothes, all them soaking wet, including my leather work boots.
Yep. Fully 50% of my mother's Anglo-Saxon tribe are asocial, quiet hermits who drink and prefer the company of animals to people.