But virtually everyone in the field does believe there are many different mechanisms behind autism, some of which have little-to-no overlap either in the mechanisms themselves or necessarily even in the presentation.
Many scientists believe that one day we will likely be able to split off at least some of the undifferentiated mass of ASD into potentially completely unrelated disorders that may share a lot of aspects of presentation.
For example, we may find out that one set of genes combined with cytokine storms in utero cause dysfunction in synaptic pruning, while another set of genes combined with gut dysbiosis may affect brain plasticity in the critical period of early childhood. Those would be two completely unrelated conditions, with overlapping symptoms for some (but not all) who have them.