I think you're greatly underestimating what it takes to mine regolith in vast quantities, transport it, produce it into something usable, then build heavy struc

I think you're greatly underestimating what it takes to mine regolith in vast quantities, transport it, produce it into something usable, then build heavy structures with automation. You're looking at 10,000+ lbs machines and many of them and with no heavy energy source. You're not running these off solar or a small RTG, so you're probably talking building a nuclear reactor on the moon just to power these juggernauts. Meanwhile human built lightweight structures are pretty much doable right now with a heavy human rated rocket like the upcoming SLS or SpaceX's upcoming heavy configuration.