And your second point is exactly correct. Not only will they compete on price, but a premium will be placed on human interaction, just like it is today.
Robots are mechanistic, deterministic machines. As such they have no consciousness, however complex their programs. Complexity of programs is a sort of "intelligence," especially if they are well-programmed. But that intelligence is an extension of their conscious makers, for instance, us.
Now, your idea of limiting "IQ" of robots is interesting. Clearly low IQ is no bar to gaining political power in our world. But any political power gained by robots would be on behalf of those who had programmed them. A person with the resources and intelligence to deploy a robot army would be powerful, the same as a CEO or general deploying a corporation or human army is. In a sense, the robots might all be avatars of the person behind them. And their sheer calculating ability might be many times his or hers, just as is true of the computers we all use today.
Robots as dangerous machines, yet powerful ones: yes. Robots as able to conduct their own civilization: no. Not until someone has the capability of endowing them with consciousness. We're no where close to that. We hardly know what direction to go to do it. It may not even be an available direction to go in. In this universe, there is some class of imaginable prospects which is nonetheless truly impossible.