The criteria for diagnosing ASD today are vastly different from those that would’ve resulted in an autism diagnosis shortly after the abolishment of lobotomy, it is hardly surprising the rate keeps going up as you widen the net.
There is no direct link, but the point is that an increasing trend in diagnosis of ASD is not surprising when the baseline is coming from a time when doctors thought cutting out parts of your brain to make you more calm was a good idea. Basically, we shouldn't look at numbers reported by doctors willing to perform lobotomies for depression as a reliable indicator of the incidence of ASD in the population at the time.