I think this a whole bunch of non-sequiturs.
First, what does commuting have to do with transport of goods or waste? The latter is quite efficient when measured as the ratio of net weight of the cargo to the tare. By the same standard, the former is very inefficient - a 4 tone SUVs carrying 200 pounds of human flesh. If that ratio was applied to cargo transport, it would bankrupt the carrier quite quickly. The only reason it works in transporting humans it is because the whole cost is shifted on the consumer and the consumer bamboozled by the industry propaganda that cars are the epitome of freedom and sex appeal, so the poor schmuck work their asses off to buy and maintain them. But it bankrupts them, eventually.
But more seriously, a lot of waste and pollution can be saved by reducing commuting by cars simply because there are many cars, almost as many as the number of commuters. The saving can be achieved either by taking off a number of cars of the road by using transit - which is more efficient if fully utilized - as well as by reducing the average commuter distance. Moreover, reducing sprawl will save even more in road construction and maintenance.
As to the alleged "unsustianability" of the cities - you must be dreaming. There would be no civilization, no technology, no medicine, no transportation, no science, no telecommunication without cities - just a bunch of bumpkins doing primitive agriculture with bare hands, hoes and oxen. The agriculture benefited enormously from the development of the cities in several ways: increased demand for food, new technology, new organization. In fact, there would be no modern agriculture without cities. There is no coincidence that the most urbanized societies also have the most efficient agriculture and the least urbanized ones - the most primitive and inefficient agriculture. Obviously, there is mutual co-dependence due to work specialization, but claiming that country side "supports" the cities or that "cities" would die without the countryside is a bunch of nonsense.
But this is an altogether different issue from the "back-to the roots" life styles of spoiled US middle classmen, attorneys, physicians, consultants, artists, etc. who earn income in the city and then buy farmhouses in the countryside pretending to be "farmers" and taking advantage of all kinds of tax breaks and subsidies. I know for the fact that upstate New York and Pennsylvania is full of that kind of developments - I presume other states have it too. I understand that this is this crowd that is most vocal about the vices of the cities and virtues of simple farm living. My response to it is that they can live any life style, or think and say what they want - just do it at their own expense without vast public subsidies that their idyllic life style receives from the government in terms of tax breaks, credits, road construction ad maintenance. I do not see why the public should pay for someone's trip, nah, free ride down the memory lane.
Why is it so difficult to understand that the US sprawled life style is extremely wasteful and unsustainable? So the choice is not really between continuation of it or changing it, but between termination of it by conscious policy choices that would control the negative impact of the change, or termination of it by "natural selection" in the market place - by inefficiency leading to impoverishment and cutbacks. Choose your poison.
Wojtek