Preferable to who? The specie does not care about the individual.
Of course, it is best for me. Healthy narcissism is needed for example.
Discussion
Preferable to Nature? My reading of your own initial post is that the rise of autism is a balancing reaction to prevalent narcissism.
Perhaps healthy narcissism includes confidence or charisma, attributes which could be helpful or underdeveloped in an autistic type, for example...
Just thinking out loud.