Materials. Different materials, different complexity, possible use of advanced bionengineering to let NatureTM build the domes, electronics, etc.etc. At least in INF, A is far easier to achieve than B. But still, the previous discussion showed that we don't have the same concept of "dome" and "Nanotech" in our mind. You think domes are masterpieces of incredible complexity, I think they're not because that would make worldhousing the Moon unplausible (so, if worldhousing of that magnitude is possible, it has to be done with cheap materials). You think Nanotech can do X and makes Y possible, but I think it can only do Z. In poor words, it's almost as if we speak two different languages.
My sincere invitation is stop discussing Luna's domes in Inferno until a proper description is published. Discussions on Nanotech are still welcome, anyway. I've quite a few ideas about it, solving all the (apparent, mind) inconsistencies, but I currently have to work on something else. This thread is about terraforming in general, so if you guys have something to say about it just say it.