Comment by anatoly

I think the definition of "profound" they chose (nonverbal, minimally verbal or IQ < 50) has much less wiggle room than the broad ASD/autism diagnosis, and also fewer incentives towards inflation. Diagnosis replacement vis-a-vis intellectual disability is still a worry, and I wish there was a way to contrast with an ID stat for the same population.

Overall am in strong agreement with you, the main thing is to nail down data and very little seems to be done towards that. I've followed these studies and articles since 2011 or so with increasing dismay. The headline-grabbing stats of "1 in X" growing every year are next to meaningless, and yet I believe much points towards prevalence of actual condition really increasing. But with scandalously amorphous definitions and abysmal longitudinal bookkeeping we don't know and can't know how much it's increasing and in what subpopulations.