A run of apocalyptic and post-apocalyptic fiction

Lately I've been reading a lot of apocalyptic and post-apocalyptic fiction. A week or two ago I finished Too Like the Lightning. Now I'm reading A Canticle for Leibowitz, listening to Wizard and Glass from The Dark Tower, and edging toward reading Ward. And I ordered another book recently that's supposed to be apocalypse-themed. It's a lot.

Too Like the Lightning is an edge case because it's not (I think) about a most-people-die apocalypse, but it fits. The prologue and events both suggest it's a time when the world ceased to work as it used to and changed drastically in a relatively short time. It's about the end of the world "as we know it"—which is still pretty unsettling.

Why this is, I don't know.

I wonder what else they might have in common. Desperation, maybe?