I suggest another study, albeit very hard to do: what if Germany have chosen de-urbanisation, observing that in the denser Nederland 81.3% of citizens live in homes not apartments, like in Belgium (77.6%) or France (62%) pushing a nation-wide program to build new homes (meaning "A class", well insulated, air-tight, with good windows, heat-pumps for heating, cooling and hot water) etc modeled as a State run real estate exchange a classic home against a new one, with some constraint like:<p>- similar size, more allowed but at citizen expense<p>- build in a locally hydro-geologically stable place (meaning a flood/landslide can arrive nearby but not in the home)<p>- only offered for PERSONAL properties, or SME enterprise direct property, not allowed to be rent for 5 years at least after that bonus<p>Obtaining as a result a sharp decrease in winter consumption for heating, summer consumption for cooling, and a bit of renewable to shift a bit of load AND a bit of semi-smart grid meaning a classic "low tariff" with pilot wires for appliances like hot water heater etc that in a new home could run a bit independently from the heated water usage?<p>IME, having built a new home, I can state a mean of 1/7 to 1/10 overall consumption compared to an old one, meaning at large an enormous reduction in energy consumption and a bit of semi-autonomy allow for less urgent intervention in case of service issues witch in general means much lower costs and easier evolution for the service side. Aside building resilience and what we damn need for future evolution.<p>A small notes for those from USA: in UE there are no USA-style suburbs, meaning even in spread living homes and commerce are normally mixed, so you normally do not need to travel much for anything, and you don't need to go to the nearest city for anything because anything is actually spread like homes. Cities on contrary are MUCH more dense than USA, to the point is practically impossible re-building simply because the construction site would disrupt the surrounding circulation in such impacting ways to be doable only in case of collapse risks.<p>A last note for all: so far many state cities cost less than living spread but there is NO REAL STUDY on that topic, especially for MODERN cities (buildings built with elevators, HVAC, ventilation, fire and seismic safety, energy performances etc etc etc not classic "just a set of stacked boxes and some stairs"). IME and IMO having done some very basic computing a MODERN set of small homes consume less alone than an equivalent building of apartments and urban infra around (sewers, drinking water, electricity, roads) cost LESS as well for spread areas where infra a smaller instead of having to sustain density.