What we have here is a popular belief which is promoted on the basis of an analysis of empirical data . It must at least stand up to scrutiny on that score, and it fails to. The technical point is important for one very real reason. If we want to change something, we need to know how it works. If we want to manipulate cities for the better, we need to know which buttons to push.
Planning is more than dreaming.
Clearly, this is a complex subject that deserves close attention and better analysis. There are good reasons for improving the range of choice in cities, including appropriate increases in density. The problem is, the graph in Fig. 1 is not one of them. The original source of this data, and the graph in Fig.1, is Newman, P. and Kenworthy, J. 'Cities and automobile dependence.