Kevin at Fortworthology posted my recent blog on the diminishing returns of density, adding his own thoughts as well. It has sparked a bit of predictable backlash which I will respond to here. My post simply stated that height doesn't necessarily = density and it certainly doesn't yield more intelligent density, ie compactness than low-scaled density of similar numbers in terms of residents per square mile or acre. Furthermore, the economist driven solution to needing more density and reducing unaffordability is to build height. As if Manhattan is affordable. No, my point is that we have to be careful that we don't allow building height to lessen the quality and character of places that made them so desirable in the first place.
As I stated in the original piece, I'm not against height indiscriminately, but rather, quite discriminate in where and when it is appropriate, desirable, and well executed. As I often say, Density = Desirability. I like that statement because density done poorly diminishes desirability. My response is mostly triggered by the notion that if you limit heights in DC or Paris there will inevitably be sprawl outside its borders. Sure, it may be lower density, but it takes on the form allowed by the rules of development and transportation infrastructure in determining what format the development will be. Because it's less desirable to be further away from the activity and amenity of the core (if healthy like Valencia) then it will be lower scaled and more affordable.
You're actually making my point about Manhattan (where the commenter suggested I wasn't fairly counting NYC's daytime/worker population in its density). Those are people commuting from long distances. Given New York's geography and water bodies that means longer than usual distances and extensive infrastructure to move people (commuters) that far. You also don't necessarily end up with sprawl. Sprawl is a by-product of the development rules in place and transportation infrastructure immediately outside DCs boundaries.
See Valencia Spain and its surroundings for an example of suburbs that aren't sprawled at all, but all about 1 mile radius in size around train stations. All are very walkable, have a range of densities/building heights (from mid- and high-rise in the larger 'pueblos' or suburbs down to single family homes), nearby jobs/industrial sectors which are quarantined as LULUs but accessible to freight rail and highways without adversely affecting neighborhoods, and are nestled within adjacent agricultural production and a predictable food supply.
These areas provide many of the "affordable" options where constrictions in supply multiplied by demand for the core city might price some people out of Valencia proper. However, because the pueblos are "complete" in that there are jobs, amenities, and services there within walking distance, as well as convenient transportation to the core cities, any of the pueblos aren't particularly dependent, but rather both in- and inter-dependent upon the core city in that they can supply the labor force of "blue collar" workers that can't or don't want to live in the city.
Or they can work in their particular town. Choice of housing and transportation is built into the system thereby making it 1) more intelligent and 2) more appropriately affordable to each's needs while maintaining opportunity of the broader metropolitan market without socio-economic segregation/alienation nor over-building of regional transportation infrastructure (highways). This is a far healthier "regional" metropolitan area than ours currently is and has yet to fully play itself out.Where Valencia's problems have occurred is the rampant spending that brought down much of the world economy. However, the majority of what was spent in Valencia will be around for more than 100 years: the extensive Ciudad des Artes and Sciencias (which gets the most flack from residents for being a $2billion euro boondoggle, and rightly so), a new high speed rail station and network interconnecting Valencia to Madrid via 80 minute train ride, and too many to count luxury high-rises. That's certainly better than actual sprawl and much of what we've built which will be gone by 2050 while Spain will still be reaping the benefits.