Thats nice. But you're missing the point. The goal is to build a city now, correct? That requires money. Money has a limited potential, it can only do so much. So with a given amount of money, how many people can we safely house and feed? THAT is the size of the city.
As far as future potential?
As I've proposed before, the city that gets built might eventually become the core of a much larger city. Few Americans realize it but most of our major, old cities were originally military forts. True, in some cases the walls have long been demolished but the campus of the original fort is still there. Atlas, might be a similar situation. It will be at the core of a much larger future city. But that future city, in whatever form it takes, is not our immediate concern. What we are concerned with is the fort... A small area, of concentrated planning, with a specific purpose.
So lets focus on the fort.
When "Detroit" was built it wasn't envisioned as a city of 140 sq miles to house +2 Million people. It was a small fort set up to launch attacks against Indian nations, which later evolved into a major center of commerce around trade with Indians, which later evolved into a major producer of marine vessels, which set it up to become a major producer of automobiles. Do you really think the guys who layed down the lines of the fort were thinking about building expressways to handle the traffic, zoning specific areas of the land for heavy industrial manufacturing (like automobiles)? I can assure you, they did not.
The honest truth is just like the settlers, we don't know what industry and technologies might evolve tomorrow. Trying to figure that out is not our concern today, because today, our concern is TODAY. "Futurists" once predicted we'd all have flying cars by the 21st century... Where are they? That prediction was more than 80 years ago. Do you see the futility in focusing on things so far out of our timeframe? That is why we focus on today...
The only thing we can do today is focus on building our fort. Who knows, maybe in 20 years teleportation will be easy and we don't need to worry about any kind of transportation system at all. That's fine and well, and possible, but not a guarantee. We need to focus on building our fort today, for a certain number of people to survive. IF it catches on, it will grow organically, as all cities have done. But you've got to lay the foundation before you start thinking about what color to paint the walls.