I have to disagree with you here, my uncle who was a prison warder lived in a village well away from Wakefield and commuted to work as do many other people.
He still lived on the same planet he worked on. I can guarantee you that with jump drives for interstellar transport people don't commute to a job in the next starsystem. Transients would travel there, stay for a number of months or even some years and then be replaced by someone else when they returned to their homeworld. Thus many transients will have the same 'footprint' as a permanent resident; he's just made up of a succession of different people.
I can quite easily see a world with a small population that is a major institution, the City of London (not the huge rambling mess outside) is quite a good example in this world.
I don't see it. An oil rig might be a good analogy, but not a major financial hub situated in the center of a huge city serviced by agricultural and manufacturing from even further away.
Hans