What would it mean for rationality to be “objectively better”? It depends what the objective is. If your objective is “predictive power,” then by some definitions you are already a rationalist.
Is your issue that predictive power isn’t a good objective, or that there are better methods for prediction than those discussed on this site?
Explain why not all humans are rationalists, then. If the paradigm of rationality has more predictive power than their paradigms.
Explain how it feels from inside, for humans, to look at rationality and fail to update, despite rationality being objectively better.
What would it mean for rationality to be “objectively better”? It depends what the objective is. If your objective is “predictive power,” then by some definitions you are already a rationalist.
Is your issue that predictive power isn’t a good objective, or that there are better methods for prediction than those discussed on this site?