The costs just to put the materials up there makes me wonder the long term viability of just trying to source it from the moon. By the time you are willing to spend the billions required it cannot be much more of step and provides other uses.
still I have to agree, how do you even maintain something like this. it would probably lead to a full time presence in space unless robotics become just that good. I just don't see the ROI except may be for national pride.