Actually, I think it's not a continuum from "productive" to "wireheading". I think there's a continuum from "immediate end-in-itself" to "delayed gratification" to "doing what's best for the future societies" (let's call this the fun vs productive continuum), and then there's a continuum in what you consider to be an end-in-itself which ranges from wireheading (max-happiness utilitarianism; good/bad is exclusively about good/bad mental state) to preference utilitarianism (what's good is defined in terms of minds, but involves stuff outside of minds) to something like "the divine aesthetic" (maximize some fully external-to-minds notion of beauty in the universe, so things like dead planets with beautiful clouds count as positive, even if they are never observed by a conscious entity).

This second spectrum is the one I'm pointing at when I say fiction is further toward wireheading.