It doesn't matter how much volume is available for development, the economics of the gravity well will ensure that only the minimum amount is made available. New sections may be added on as required, but space will always be at a premium.

Remember 2001? How much wasted space there was on the shuttle, the space station, the moonbase? The film was technically correct, but the space program of the future wasn't very realistic otherwise. Will we really need a great elevator to lower arriving spacecraft deep into the regolith?

You've come a long way, Robert, but you're still a space groupie at heart. You dream of terraforming Mars but look at what happened to Earth.

Remember Andy Rooney's comment on the Veranzano Narrows bridge?

"Man has made a sewer of the river, and spanned it with a poem."