If raised in an affluent suburb, they might surprise you.
Speaking of which, have you seen the _Project Nim_ documentary on https://en.wikipedia.org/wiki/Nim_Chimpsky ? I would have to say that no, he did not surprise me, and the results were exactly what I would have expected after reading de Waal's _Chimpanzee Politics_.
Of course, genetics probably plays a role in that, too.
Of course genetics plays a role in intelligence (a very important role). In the case of chimps they are not part of the human population so they are not really relevant to any discussion about the genetics of human intelligence.