As I thought. Makes sense that something that absurdly expensive even on a galactic scale would only be used for places actually worth the cost due to losing said places being too heavy a blow to consider like Vanaheim AKA the main shipyard of the Trust would be for us. Imagine that even the major polities would only be willing to have a very small handful with a polity like Callamus maybe having several for their most largest and productive Forgeworlds.
@Durin
1) How many Heaven Fortresses are the rest of the major human polities considering?
-1a) What kind of places would they used to defend?
2) Are there more instances of chaos polities working together thanks to the Orks awakening putting pressure on certain polities?
-2a) Are the rest of the human polities a lot more willing to work with the Eldar in the current age when it comes to preventing things like level 4 Waaaghs?