Expected performance is what rational agents are actually maximising.

Whether that corresponds to actual performance depends on what their expectations are. What their expectations are typically depends on their history - and the past is not necessarily a good guide to the future.

Highly rational agents can still lose. Rational actions (that follow the laws of induction and deduction applied to their sense data) are not necessarily the actions that win.

Rational agents try to win - and base their efforts on their expectations. Whether they actually win depends on whether their expectations are correct. In my view, attempts to link rationality directly to "winning" miss the distinction between actual and expected utility.

There are reasons for associations between expected performance and actual performance. Indeed, those associations are why agents have the expectations they do. However, the association is statistical in nature.

Dissect the brain of a rational agent, and it is its expected utility that is being maximised. Its actual utility is usually not something that is completely under its control.

It's important not to define the "rational action" as "the action that wins". Whether an action is rational or not should be a function of an agent's sense data up to that point - and should not vary depending on environmental factors which the agent knows nothing about. Otherwise, the rationality of an action is not properly defined from an agent's point of view.

I don't think that the excuses humans use for failures is an issue here.

Behaving rationally is not the only virtue needed for success. For example, you also need to enter situations with appropriate priors.

Only if you want rationality to be the sole virtue, should "but I was behaving rationally" be the ultimate defense against an inquisition.

Rationality is good, but to win, you also need effort, persistence, good priors, etc - and it would be very, very bad form to attempt to bundle all those into the notion of being "rational".