Research has shown that a barren environment is much more damaging to baby animals than it is to adult animals. It does not hurt the adult animals the same way it damages babies.
Research is starting to show that a child should be engaged at least 20 hours a week. I do not think it matters which program you choose as long as it keeps the child actively engaged with the therapist, teacher, or parent for at least 20 hours a week.
Some autistic children cannot stand the sound of certain voices. I have come across cases where teachers tell me that certain children have problems with their voice or another person's voice. This problem tends to be related to high-pitched ladies' voices.
When you take a drug to treat high blood pressure or diabetes, you have an objective test to measure blood pressure and the amount of sugar in the blood. It is straight-forward. With autism, you are looking for changes in behavior.