This is such a great observation, and I definitely think a big part of the appeal of post-apocalyptic fiction for a certain kind of reader and writer is that you get to wipe out huge swaths of human complexity with “They all just die but it’s not eugenics because the zombies did it.”
But I don’t think it has to be that way, and I think a solarpunk approach could be a great way to bring that out. It would be harder to write, sure, because if the nature of a setting is to say “any shortcoming is a justification for letting someone die,” then it’s got to be a much bigger deal to the protagonists to resist that kind of thinking.
But that also makes it a great kind of story to showcase exactly the kind of values it’s often used to condemn: to show a group retrofitting their friend’s wheelchair with a solar powered motor and all-terrain wheels, or using precious power and backpack space to keep a supply of insulin refrigerated, or all learning sign language to accommodate their deaf teammate.
You could show people not failing because they chose compassion over pragmatism — maybe even succeeding because of it. All three of those accommodations have advantages, too: the group member with a powered wheelchair can probably carry more than other group members,* if you’re hauling a fridge you can refrigerate more than just insulin, and sign language is a valuable silent form of communication if you’re in a world filled with hostile zombies.
The important thing is to show groups choosing to stick up for their disabled or neurodivergent** members and not be punished for it. Those group members don’t need to ultimately be the climactic key to success — in fact, that’d probably be a problematic way to take it, because it would end up re-emphasizing the idea that their value comes from their ability to be useful.
But showing them as fully realized contributing characters in the story, whose teammates care about and support them (and vice versa), and showing them all make it out alive, flies in opposition to the ableist nature of apocalyptic fiction.
Of course, fiction where the world as it exists doesn’t have to end for things to start to get better is also important. But I can see a lot of value in post-apocalyptic fiction that isn’t a thinly veiled excuse to start gleefully describing the tragic deaths of everybody not optimally equipped to serve the new libertarian/military grim utopia.
* I’m not actually sure about this point — if anyone reading has personal experience with the physics and practical concerns of using a wheelchair re: carrying capacity, and wants to correct me, please do.
** I know I don’t actually have any examples of neurodivergence in the post. I’m gonna keep thinking about that aspect of this but I don’t have anything atm.