Without autism there would be plenty of other things to try to cure. Mental retardation, ADD/ADHD, Tourette's, schizophrenia, anxiety disorder, bipolar disorder, being psychotic or sociopathic - all of these would be enough to keep the world interesting. No mental institutions would be harmed in the making of an autism cure.
People with extreme autism would benefit from being able to look after themselves instead of having to count on someone else. People with less extreme autism would find it easier to fit in, make friends and find emotional support. Not all nerds have AS, so bullies would still have plenty to eat.
Research and development would not be affected that much. I agree that genius is not restricted to the spectrum. Without the hyperfocusing, some hard science would be less developed. It's impossible to predict how much longer research would take or how big of a difference it would make in the meantime.
In all, science would see fewer quantum leaps, but how many fewer is not knowable. Maybe one of them would be the big one that saves mankind, and maybe not.
We're here because some of us are needed for specific things. Who and for what is a mystery. One thing, though - there will be a cure when we're no longer needed. Enjoy the time left afterward because it will be short.
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To eliminate poverty, you have to eliminate at least three things: time, the bell curve and the Pauli Exclusion Principle. Have fun.