If it's genetic, as you assert, then what hope is there?
I believe you're correct, but ...
> because parents prefer it, again because it offers more hope
This sort of thinking is popular because it offers hope and having that hope present offers a higher quality of life for the family.
Recognizing what their specific problems actually are, there is significant variation in the strength of the particular difficulties individual autistics face.
Teaching autistics to work around their disabilities; there has been significant progress on this approach for recognizing and dealing with other peoples emotions, for example.
Getting them the support they need for problems they cannot work around.
Drugs which target the specific pathways triggered by the gene.
Um... plenty? Tons of genetic diseases are treatable. This is where Genzyme, for example, makes most of its money. Cerezyme for Gaucher's disease or Fabrazyme for Fabry disease to name two.