Not saying you're wrong at all (in fact I agree), but I think that an important thing to remember is that smart people still have limited time like everyone els

Not saying you're wrong at all (in fact I agree), but I think that an important thing to remember is that smart people still have limited time like everyone else, hence they will probably be less enthusiastic to fritter it away on "meaningless" social interaction and small-talk when they could be doing something they consider useful, challenging or stimulating. This tendency IMO tends to make some smart people less adept at social interaction, just because they do less of it. Not all smart people, but definitely some of them. Probably everyone knows an intelligent person who is socially awkward. So that's another influence. But it's all generalizations.