Is this true? I think story-telling has been generally prioritized by humans at most place and times. It is not obvious to me we invest far more than our ancestors, I doubt it.
But the OP is some interesting ideas, I'm still trying to figure out the implications.
> Our moral evaluations of the main big actions that influence our world today, and that built our world from past worlds, are still up for grabs. And the more we build such shared evaluations, the more we’ll be able to tell satisfying stories set in the world in which we live, rather than set in the fantasy and historical worlds with which we must now make do.
Hmm. I think some of the best stories help us work out our moral evaluations and build shared ones. This isn't just something that happens outside of fiction and then affects our consumption of fiction -- fiction, for the reasons the OP outlines in fact, is one of our tools for working it out. We build shared evaluations by telling stories. Story-telling is fundamental to how humans make sense of the world, moral and otherwise, but moral too. I think OP would agree? That is in fact why we fight over it, because we know how powerful it is in this area? Not sure.
As a devotee of speculative fiction, I'm a bit offended at the framing that it is something we must "make do" with out of our moral confusion. Like any other genre, there is good and bad, but I think at it's best SF can be a notably valauble tool in helping us self-reflect and develop our moral sensibilities, it is in fact a power that SF has particularly. Sure, there's plenty of lazy SF that avoids reflection or difficult questions, but at it's best it has a particular power to challenge in a way that builds new understandings, precisely by inviting the reader to look at things with fresh eyes instead of the comfort of the familiar and legible.