Kant's argument only needs the weaker claim that rationality requires willing the development of some of one's talents

By contrast with the maxim of the lying promise, we can easily conceive of adopting a maxim of refusing to develop any of our talents in a world in which that maxim is a universal law of nature. It would undoubtedly be a world more primitive than our own, but pursuing such a policy is still conceivable in it. However, it is not, Kant argues, possible to rationally will this maxim in such a world. The argument for why this is so, however, is not obvious, and some of Kant’s thinking seems hardly c