To the extent they define a particular idealization it’s one which isn’t interesting/compelling. What one would want to have to say there was a well defined question here is a single definition of what a rational agent is that everyone agreed on which one could then show favored such and such decision theory.
To put the point differently you and I can agree on absolutely every fact about the world and mathematics and yet disagree about which is the best decision theory because we simply mean slightly different things by rational agent. Moreover, there is no clear practical difference which presses us to use one definition or another like the practical usefulness of the aspects of the definition of rational agreement which yield the outcomes that all the theories agree on.
To the extent they define a particular idealization it’s one which isn’t interesting/compelling. What one would want to have to say there was a well defined question here is a single definition of what a rational agent is that everyone agreed on which one could then show favored such and such decision theory.
To put the point differently you and I can agree on absolutely every fact about the world and mathematics and yet disagree about which is the best decision theory because we simply mean slightly different things by rational agent. Moreover, there is no clear practical difference which presses us to use one definition or another like the practical usefulness of the aspects of the definition of rational agreement which yield the outcomes that all the theories agree on.