We already have "superintelligences" in the world; Nature and other humans treated as a collective is far more powerful than any individual. We manage these risks by not trusting them completely, and restricting their dominance over us. I don't see that we can't adapt to superintelligent machines as long as we don't surrender all decision making to them; the risk comes from the same old, where a group possesses overwhelming power that is then used to regiment and oppress a less powerful group. In which case, possession of AI is far from unique.