The word suburbanization generally refers to development outside of, and often geographically separated from, the population of a central city, but still socially and economically dependent on it. Suburban development is typically (but not always) less dense, diverse, and self-sufficient than its urban counterpart.
However, contrary to popular belief, suburbanization was not strictly a post-WWII penomenon. There was some suburbanization before WWII, but it paled in scale to what came afterward. Also, the vast majority of pre-WWII sprawl was not automobile-based, so 'sprawl' was not the large problem in the way that we now know it. (Incidentally, most pre-WWII suburbs were known as 'streetcar suburbs,' a term you may have heard of.)
Locally, it took until the 1930s to fully urbanize the 42 square miles within the city limits of Buffalo, so until then there was not a whole lot of pressure to develop much further out. Furthermore, pre-WWII development in the Buffalo area was driven generally by population growth, so it could be accurately referred to as 'growth.' Real growth, if you will. On the other hand, most post-WWII development in this area was (and continues to be) low-density, automobile-based, and not driven by population growth. So it's not real growth. Because of this, the type of sprawl we have here is considered, perhaps, the purest type of sprawl, and has arguably resulted in its worst effects.
A few commenters mentioned the fact that there are fewer people per household today than in 1950, so naturally there are more households today for the same number of people. Yes, household size is smaller today, but this still doesn't account for the increase in housing units. Strictly by the numbers one commenter provided, from 1950-2000, housing construction outpaced shrinking household size in the Buffalo area by 119%.
While not as stark as the statistics for urbanized area, these numbers only add to the already bad news. Shrinking household size doesn't aquit the many defenders of sprawl that come out of the woodwork to remark on this topic; the numbers only magnify the already obvious problem.
For a real eye-opener, I direct you to the Brookings Institution study, Vacating the City: An Analysis of New Homes vs. Household Growth. Figure 1, reproduced from that report, tells the somber tale (see graphic at right). The Buffalo area had by far the worst numbers of any of the 70 metro areas studied: "While the Buffalo area had household growth of only 1.5 percent for the entire decade of the 1990s, almost four units of housing were built for each additional household."
Wow. As if that wasn't bad enough, the comparisons with other areas indicate the extent of our perverse lead. When measuring building permits and household change from 1990–2000, Metro Buffalo was first (worst) at 289%, followed by Pittsburgh, PA (191%); Scranton-Wilkes-Barre Hazleton, PA (153%); Youngstown-Warren, OH (134%); and Dayton-Springfield, OH (121%).
An intelligent discussion
Now that we've got all that straightened out, here's the 'intelligent discussion' part alluded to earlier: Metro Buffalo hasn't really grown in about a half century. The area has, however, sprawled. The fact remains that if Metro Buffalo had not sprawled starting after WWII, or only sprawled a little, we wouldn't have the redundant infrastructure, extra government, soaring costs, and poverty/blight issues we have today. We'd have had the necessary concentration of people, ideas, and resources to weather deindustrialization and the other economic and social changes that befell the Rust Belt. We'd be much better off than we are today.
Unfortunately, we can't change the past. But we can learn from it. Today, recognizing and understanding the overall causes of sprawl as we do, we'd be stupid not to do something about it. This is not to denigrate anyone's individual choices. This problem is far bigger than any single person. This has to do with larger economic, governmental, and cultural systems that have driven large-scale trends over decades of time.
The bottom line is that the system as it stands is rigged; it is incentivized for sprawl. In large part, the system was set-up to produce the exact outcomes we see today. The system will continue to produce the same result if nothing is done to change it.
However, the system we've got was not the result of some absurd government conspiracy. Most of the policies in land-use, transportation, finance, and governance that drive the current system were intended to solve the legitimate problems of an earlier time. They were created in a day when urban and economic problems were quite different and the automobile was seen (naively) as the sole savior of our transportation troubles.
Today we've got new problems, many of which were ironically caused by the old policies. These new problems require a new set of solutions. Transportation policy, land-use laws, and governmental structures will all have to change. And they will change; we'll be compelled at some crisis point to do so. But how big does the crisis have to get? And will the problem at that point be too big—and the resources too scarce—to fix?
So, the real question is this: As a region, are we able to recognize the new reality and adjust quickly and wisely? Perhaps if we all begin to understand the subject better we can actually start having an intelligent public discussion. Thus far, however, we haven't shown much of an ability to form any kind of coherent consensus.