I would think there is not enough money - or call - for permanent structures here. It would be like oil rigs out to sea - eventually the local resource would be used up and the city would need to move again anyway. In any case, I really like this city image - it paints a very clear picture for me and is a fascinating locale. In some ways it feels star-wars-ish,
Its good, but does not really provide a city image in the manner that the whole City Image thread seems to request. A clear visual description should have started this off, and then led to other details.