“While the definition has been greatly enlarged, it does not account for all of the growth in prevalence—or severity.”
Prove it.
“Professionals who have been in the field all their adult lives and are nearing retirement have confirmed this trend firsthand.”
Data please,
Research please.
And as I pointed out, direct longitudinal observation by professionals confirms this. I have spoken with such professionals myself, so there's convincing professional anecdotal evidence, perhaps even formal clinical research.
There's a lot of good and bad research on autism, but I'm sure you can go through it to see if it can provide support to your assertion. Burden of proof is on you--who made the initial claim.