Tides wrote:It's not a typical post-nuclear setting but it is post-apocalyptic setting nonetheless.
It's post-apocalyptic setting in the same way, as early medieval Europe was. Ruins and ancient junk everywhere, new factions, forests with no end, dominance of animal predators, etc.
If you see it from that persepective, then yes - Numenera is 'post-apocalyptic'.
But bear in mind, that there are literally tons of classic fantasy settings, which are as much, as 'post-apocalyptic'. And no one calls them that. Because, it's broadest possible definition of "post-apocalyptic" descriptor. You're free to do that, but others are free to disregard your definition
, if they think it's not fitting. What "post-apocalyptic" descriptor usually implies, it's a dystopic future after end of the world as we know it - either one or series of massive extinction events with remnants of humanity attempt to survive and reform society. Some can argue, that 'post-apocalyptic' fantasy settings are already a huge stretch for that sub-genre descriptor.
What we have in Numenera's Ninth World is quasimedieval society, built by colonists from beyond on a uninhabited land, which is littered with ruins of ancient civilzations and their archeological artifacts. There are no reference to any particular massive exctintion event and most of settings inhabitants are not descendants of survivors.
So, there is no connection between any part of game setting, that makes it reasonable to call it post-apocalyptic setting, other than that there's no signs of 20th century civilzation around (and that's unrealistic expectation to find any after one billion of years, I must add) and your own desire to call it that way to promote your idea of spawning mobs in a game, that is already made differently.