Are questions which basically boil down to setting up primitive civilisations on topic on TGO?
Yes, for topics that require deep engagement with The Great Outdoors.
What do I mean by deep engagement? I mean working with natural resources from The Great Outdoors, potentially (or even likely) in The Great Outdoors, primarily for appreciating The Great Outdoors, and in a way that is possible to do today without excessive damage to The Great Outdoors.
Each of those points is important. Maybe we can refine that criteria further but that is my starting point: If a question has to do with some kind of craft that is sourced from, practiced in, for appreciation of, and without excessive damage to The Great Outdoors - it's relevant.
That said, I think the iron question is reasonable. I actually hope to try it out as an extension of my interest in bushcraft and primitive skills - interests which continue to enhance my appreciation of TGO. I realize that is a stretch though - more realistic to make rope or an axe. Accordingly, as I do more research I see that the copper question is a lot less appropriate for TGO.SE because it is not realistic that I could source the materials from The Great Outdoors and not do excessive damage to The Great Outdoors.
Questions about survivalism, as I have said elsewhere on meta.TGO.SE, really are not suitable for any one SE. There is so much overlap with so many topics that I don't think any one SE could appropriately house them all. That said, many survivalism topics (the majority when it comes to short-term rescue-oriented survival) do fit in TGO.SE and with the criteria I put forth above. That's why it's good we have relevant tags: survival, primitive-tools, wilderness, diy, rescue, safety, first-aid, navigation.
Questions about where to find minerals may be better suited for Earth Science SE if that is the main focus in and of itself, or if the main focus is on finding those minerals as a way to engage in The Great Outdoors in accordance with the suitability criteria suggested above, then it could be appropriate here.