Exactly my thoughts. The reason why autism diagnosis rises is because it’s ill defined, the definition describes autistic symptoms not autism. Evidently the profession is rather confused as to what autism actually is. This pollutes the patient base, which in turn makes all research invalid since it’s unknown if participants in studies has autism or only autistic symptoms. This circular logic is the source of present day lack of common cause findings. The common cause is simple, altered white matter in the fetus leads to specific altered neural pathways resulting in a different structure of grey matter due to the neural feedback being directed differently. Which in turn reinforces white matter structures. After birth the job gets finished via environmental input.
The origin of this is imho evolutionary try-outs of getting rid of the hindrance of limbic system supremacy in societal living.
Where a million years ago the limbic system was perfectly capable to handle all events, nowadays it’s completely outclassed and outdated resulting in negative survival indices. Emotional/limbic reactions are a serious threat to human existence.