Do a Mars colony next.
And now imagine doing this in a world where there was no federal tax, the GDP was pennies (relative to today), and state of the art technology was us being on the verge of discovering that handwashing before surgery was a good idea. Really! [1] And the big goal here was to be able to put up 'electric lanterns.' It sounds so pie in the sky as to be unbelievable. And indeed it probably would never, in a million years, happen today. But it did happen in the past, and for that we owe our predecessors quite the debt!
The point I make with this is that we have just an unimaginably vast level of economic power today, but it's mostly being squandered. We should be trying out grand ideas, endlessly. If we can make them work - awesome, we've radically improved the world and humanity - our descendants will thank us. If they fail, we can call it a jobs program -- certainly a much better one than trying to make stuff to go kill people half way around the globe.
But that's not what we did. Folks at the start of the process might have imagined that eventual situation, but they built up small networks, then a skeleton network with human connections (telegraph), then human driven routing. You can't just point at those mega infrastructure items we already have and say oh we have that so we can just apply that to another because that glosses over the whole and very long process of getting from mini projects to mega ones.
The Line was designed to be literally modular, being made up of 135 modules of less than a km in length each. That such a "vision" is considered exceptional, to the point of even not being realistic, is something that to me feels like a complete deterioration of the vision and ambition in society.
