I.Q. Differentials..?

Okay, so considering how the average I.Q. is about 100, is it not crazy how it is the same difference between a mentally retarded person (around 70) and someone with superior intelligence (around 130). They are both about the same amount from the average. It has to question how people with higher intelligences fit so much more easily into society than someone with the I.Q. of 70 or lower. Of course this all just me speculating, I want to know what other people think..