AI's aim is not to adopt poor strategies. It seeks to optimize, but the point is you can lead it to believe a point is global optimum, when in fact it is only local optimum.

As to your point about the EV, this is why collusion can work. By colluding over a long enough horizon, the AI can believe that the average expected value to be something that it is not. If only one individual feign a weakness and the rest do not, then the strategy doesn't work.