Higher IQ is probably good for humanity so long as everyone has to hustle for sustenance. When a society is so wealthy that the super-intelligent don’t have to work but live off the labor of the average and lower intellects then that superintelligence becomes a liability to survival of the society. Is this, perhaps, an application of the Peter Principle?
We seem to have the opposite problem now. The average and lower intellects live off the work of the "super" intelligent (if they're so intelligent, why are they the ones working).
It seems to me this is a much larger liability to the survival of a civil society. When the "intelligent" smarten up, they just stop working.
My personal opinion is that the IQ of any individual is not representative of their 'goodness'. I have encountered very few nonintellectual individuals at two years old. And all that I have encountered at the age of two are the epitome of narcissism in varying degrees. I am NOT impressed with the supposed calculated IQ of any individual. My personal observation of the supposed genius of old bjClinton absolved of me any respect that having high IQ could represent the moral fiber of any individual.
I personally do not think 'wealth' is necessarily the principle of 'Peter'. There always seems to be some 'con-artist' genius that can make enough people believe their con that no matter the wealth things look better on the other side of the fence. I just do not consider the intellect of a flesh brain accounts for the spirit/will of any individual.