isn't there something in the med lit about tumour necrosis, where a tumour becomes so large and dense that it squeezes or displaces the blood vessels to its own interior?  I'll google for it later.  there may be an effective structural size limit for various layouts of city design;  there are physical reasons why we don't have ants the size of dogs, or dogs the size of abrams tanks.  similar laws of scale may well apply to concentrations of human dwelling and commerce.  we may think we can cheat those design laws by throwing fossil fuel at the problem, but I think it only postpones the structural limit by a few generations.

The difference between theory and practise in practise ...