eric76, to address your first point, our hypothesis addresses questions from numerous fields, such as evolutionary psychology, general psychology, abnormal psychology, archaeology, cultural anthropology, genetics, neuroscience, linguistics, etc. Now while there are certainly experts in all of these fields, no one person is an expert in ALL of them. Our research group feels that one reason this hypothesis has yet to be proposed is due to the highly specialized nature of graduate and postgraduate studies, in which many academics end up becoming laypeople in their own fields. We are trying to correct that tunnel vision by connecting different fields and utilizing multiple lines of evidence.
As to your second point, that is exactly what we are arguing. A new type of human emerged from those harsh conditions which absorbed autism into its gene pool. Autistic humans would not have survived except in the pockets of environmental stability which did exist, although we believe those autistic bands were eventually also absorbed. However, we question whether the developmental delay in autism is socially constructed. To the point, we feel it is only a delay from the point of view of what we call lupinistic development. We think that young autistic children almost immediately set about their niche construction, which involves making and learning to use tools. We think this is why they ignore people in favor of objects and why they stack and line up objects -- in the ancestral environment there wouldn't have been toys to stack up and stuffed animals to line up, but there would have been a lot of rocks, and the lithic industry was vital to the survival of early humans.