To make and keep the upper stories of a tall building habitable requires routine high technology. The lifts have to work, the water needs to be pumped, the toilets have let the poop down one hundred stories without shattering violence. It is not all that expensive. Current office space costs in the centers of major cities are so high that very tall buildings are immensely profitable. It is simply difficult to do, requires able people working together, both initially to build the systems, and subsequently to keep them going.
It is habitable floors that are hard to do, and habitable floors are what generates the rental income. So, to assess a society’s technological level, count habitable floors.
By and large, the taller the building, the more the profit. Doubtless there is a limit, but in the center of most major cities, most tall buildings are below that limit. If people could build taller, they would. At our present technological level, settling space seems likely to be fatally unprofitable, but building upwards, building the city of tomorrow, is highly profitable. (more…)