Rather than look at moving San Fran to Omaha, think of it as making San Fran, San Jose, Sacramento & a number of the cities/towns in between "one place".
If I take Tokyo as an example there is no denying it is huge, probably too big at 10m in the urban area and a further 15m in the outer urban areas. But the important thing is that for a relatively low cost you can get from anywhere to anywhere else in 30-60 minutes. And even a short walk from the busiest train station in the world (Shinjuku, close to 4m people a day) you can own a semi-detached house of your own for less than $1m (roughly).
One of the big moves here in Australia is to make Sydney & Melbourne 30 minute cities. The idea being that people generally only travel 30 minutes each way to work every day. It's based on the idea of the city having multiple CBDs (Central Business Districts/Downtown areas) so someone who works in the Sydney based one can live within 30 minutes of it, while someone who works in the Parramatta based CBD can live further away from Sydney.
In principle it's a great idea, in practice I know a lot of people who commute for well over an hour each way to work in the Sydney CBD and my wife commutes the other way from our inner city residence to her job in the third (and furthest inland) CBD area and is considering quitting after just a few months.
My personal feeling (and I should add that while I do haThe same as the Portland/Vancouver/The same as the Portland/Vancouver/ve extensive local government experience I am not a town/traffic/transit planner, engineer or anything similar) is that the largest problem is that currently virtually all major transport routes are predicated on getting to the original Sydney CBD. Want to get from Cronulla to Parramatta by train, well you get a train to the Sydney CBD and then get one out to Parramatta, a trip that takes almost 2 hours. There is no option by bus, so you drive and travel less than half the distance in 1/3 the time (except for traffic); now the roads from Cronulla to Parramatta are not large freeways designed to move thousands of cars per hour so it's stop start at traffic lights and a generally sub-par experience. So in reality you are most likely to decide to work in the Sydney CBD.
Tokyo & other mega-cities tend to have a lot of crisscrossing or overlapping mass transit systems and roads to make it easier to get from A to B, regardless of their orientation to the historic spot where the first GPO was built.
Personal Story Time, feel free to stop reading here:
Last night I attended the birthday drinks of an old friend. Our friendship is old enough to legally drink in any state of America now. It was the first time I'd seen him in years, despite the fact we live relatively close (as the crow flies) because of that CBD centric transit system, we go out and socialise in different areas. I caught up with a lot of friends last night including an ex girlfriend and another very very dear friend who again I don't see because for either of us to visit requires an hour or more on a train or in a car.
Surprisingly it is Uber that has actually improved my attendance at events like this. Now I can for a relatively low cost go home on the shorter third side of the triangle and not have to worry about changing trains/buses or staying sober to drive home (and hoping every other road user stays sober too).