Not sure if your program of choice does the same, but in Poser you can use the grouping tool to create individual props from static environments. Still, that should have been done by the vendor. Completely static environments don’t make sense to me either.
I don’t think DAZ does that. I could load the file into Blender and split everything up there but that’s just too much work at this point.
I never did get Poser. Never saw any upgrade pricing. Only price I saw was $129.95 and that’s the normal price for the upgrade and I just can’t justify spending that much for Poser.