Silly to assume that traditional aborigines were less intelligent. They knew the names and properties of thousands of plants, how to hunt, where to find water, and how to avoid getting bit by poisonous snakes. They also had highly developed music, art and oral traditions.
Intelligence is a slippery concept. In the west, it has been reduced mostly to the ability to manipulate verbal and mathematical symbols. But there are at least 9 Types of Intelligence according to one psychologist.
I think that Aspies are defined by limited social intelligence, but many compensate in other areas of intelligence.