The Infinite Expanse of Age of Sigmar

I've been seeing some negativity lately on the Age of Sigmar Facebook groups I follow toward the recent uptick in homemade warscrolls.  Namely, towards the various 40k homebrew projects floating about (most recently these Tyranids rebranded as "Cosmic Horrors").  Obviously I feel differently, but I think it's worth discussing why I feel differently.  It's not just a "we can play however we want!" situation, I think the fluff of Age of Sigmar uniquely lends itself to very, very, very open play and storytelling.

So the setting of Age of Sigmar is nine infinitely large realms (eight of which are "mortal") each of which is attuned to one of the lores of magic from oldhammer (and then Chaos).  While they are connected by magic and portals and whathaveyou, geographically they are completely distinct and separate.  So we have a collection of 9 alternate realities similar to the D&D Feywild and Shadowfell, where they are elementally attuned, but similar to eachother, but in this case there is no "prime material plane".  But wait, instead of each plane being a planet or something, it's actually a whole infinite expanse with its own moons, planets, space, and so forth.

So let's take for example Azyr, the Realm of Heavens.  In AoS, it's the realm that Sigmar has on lockdown where reasonable people hang out.  But that's probably only part of it... it is infinite after all.  There are planets in the sky!  Given infinite space, for every unique segment of space, there should (statistically speaking) be an identical segment of space.  Similarly, for every conceivable finite space, there should be a segment of the infinite space that is exactly as conceived.  All this is a bit more than is necessary though to support my point, which is that the entirety of 40k could easily be set within Azyr, somewhere in those glittering heavens.  Somewhere in the infinite expanse is a segment of space that is exactly identical to all of those cool maps in the 40k books where the exact events laid out in 40k fluff have transpired.

Similarly, somewhere in the Realm of Shadows, I imagine there is an a place called Malifaux (warning: I may make warscrolls for this, although I can't imagine it would interplay all that well).  Perhaps in the Realm of Beasts some bold humans have carved out a Cygnaran Kingdom with the might of their warjacks.  The point being, the fluff for Age of Sigmar supports and envelops all other fluffs.  Because Age of Sigmar is so vague and expansive, it seems like there's no good reason for any given thing to not exist... right?