Autism is a developmental disorder, not an emotional one. It is evident in very young children less than a year old who have not experienced trauma and who have been loved and cared for.
Children who have experienced severe neglect may shut down and stop interacting with others, but that is a different disorder.
“who have not experienced trauma”
There is much more to the process than what you describe. I’ve worked with it extensively. More Asperger’s end of the autism spectrum, but the symptoms and brain pathology are similar.
“Autism is a developmental disorder, not an emotional one.”
100% of developmental disorders involve emotional influences, often lack thereof.