Buffalo, Cleveland, Detroit, Pittsburgh, St Louis, there are all cities that have lost industry, and (unlike Northeastern cities) have had difficulty compensating with other economic sectors, and have all experienced substantial population loss.
Buffalo is in the Metro area that has experienced the least growth since 1950 (4%) but is known for nonetheless tripling the metro's built up area in an iconic example of sprawl. Pittsburgh's metro barely grew too (6%) and the city proper is starting to be known for experiencing a turn around, being the only one of these five cities to have an estimated population gain from 2010 to 2012.
The other cities have experienced moderate post-WWII growth within their metros (42-66%). Detroit is the poster child for urban decline with bombed out neighbourhoods, boarded up buildings, urban prairie, bankruptcy and crime, despite total population loss post WWII for the city proper being relatively comparable to the four other cities.
St. Louis, despite being in the metro that grew most post-WWII, has experienced the greatest post-WWII population loss among major American cities. Cleveland's reputation is generally not as bad as Detroit's, but it is nonetheless still struggling. While Pittsburgh has stabilized and Buffalo and St Louis are getting there, Cleveland and especially Detroit are still losing population at a fast pace.
1950 Population: 1,849,568
2010 Population: 713,777
1950-2010 Change: -61.4%
2000-2010 Change: -25.0%
2010-2012 Change: -1.7% (estimate)
1950-2010 Metro Change: +42%
2000-2010 Metro Change: -3.3%
2010-2012 Metro Change: -0.10% (estimate)
1950 Population: 914,808
2010 Population: 396,815
1950-2010 Change: -56.6%
2000-2010 Change: -16.9%
2010-2012 Change: -1.5% (estimate)
1950-2010 Metro Change: +42%
2000-2010 Metro Change: -3.3%
2010-2012 Metro Change: -0.66% (estimate)
1950 Population: 856,796
2010 Population: 319,294
1950-2010 Change: -62.7%
2000-2010 Change: -8.3%
2010-2012 Change: -0.4% (estimate)
1950-2010 Metro Change: +66%
2000-2010 Metro Change: +4.2%
2010-2012 Metro Change: +0.29% (estimate)
Buffalo1950 Population: 580,132
2010 Population: 261,310
1950-2010 Change: -55.0%
2000-2010 Change: -10.7%
2010-2012 Change: -0.7% (estimate)
1950-2010 Metro Change: +4%
2000-2010 Metro Change: -3.0%
2010-2012 Metro Change: -0.11% (estimate)
1950 Population: 676,806
2010 Population: 305,704
1950-2010 Change: -54.8%
2000-2010 Change: -8.6%
2010-2012 Change: 0.2% (estimate)
1950-2010 Metro Change: +6%
2000-2010 Metro Change: -3.1%
2010-2012 Metro Change: +0.19% (estimate)
Interestingly, these 5 cities have an inverse relationship between metro population change and city population change post WWII.
Although there is some optimism and investment in the core, Detroit is continuing to lose population rapidly, at a greater rate than the other 4 cities. Detroit also had the 2nd fastest growing suburbs from 2000-2010 (after St. Louis'), continuing with the 2012 estimates, despite having the greatest city decline during the same period.
To provide some additional information, I've divided these cities into "districts" and looked at 1950 to 2010 population changes. These averaged out at about 75,000 people in 1950 and 35,000 people in 2010, with their exact size being a compromise between sensible boundaries for relatively homogeneous/distinct areas, and keeping the size roughly equal.
Although the trend is mostly one of greater population loss as you move closer and closer to the core, the East side did lose a bit more population while the Southwest lost less (Delray excepted).
Median household incomes in Cleveland are $25,371. The West side is a bit wealthier than the East side, but interestingly parts of the East side are bouncing back with increasing incomes (despite no increase city wide), especially areas in between Downtown and University Circle.
Pittsburgh (includes Mount Oliver)
Pittsburgh experienced steeper population loss in the core as well, but this trend is weaker than in the other cities. It is actually the inner North side that lost the most population, rather than Downtown-Strip-Hill District. Additionally, Oakland, while adjacent to downtown, experienced the second smallest losses. Much of Oakland has very low household incomes (students I'm guessing?), as does the Hill District, however, the near South and North sides are more working class than poor, Downtown and the Strip district are middle class, and Squirrel Hill which is more inner suburban in character is upper middle class or even wealthy.
Ovreall, there appears to be a very close relationship between population change and income change.
City 2000: $29,526
City 2011: $25,193
City 2000: $25,928
City 2011: $25,371
City 2000: $27,156
City 2011: $32,570
City 2000: $24,536
City 2011: $29,158
City 2000: $28,588
City 2011: $35,947
Detroit's outer NW and NE areas, where most of the population lives and haven't been losing population as intensely in the past (which is starting to change) have experienced major decreases in income
Another interesting statistic is the number of people, who in 1950, lived in districts that have since lost over 60% of their population.
Detroit: 1,097,241 people (59.3% of city, 79.0% loss)
Cleveland: 341,713 people (37.4% of city, 75.5% loss)
St Louis: 598,840 people (69.9% of city, 72.4% loss)
Buffalo: 261,310 people (50.5% of city, 72.4% loss)
Pittsburgh: 236,495 people (34.5% of city, 65.5% loss)
The parts of Detroit that experienced significant losses are bigger and worse than for Cleveland, Buffalo and Pittsburgh. Compared to Detroit, they cover a smaller share of the city, however, the city of Detroit is much larger and the losses have been more intense.
Detroit experienced more intense decline over a larger area completely surrounding downtown than any other major American city. Other cities (Cleveland, Buffalo and Pittsburgh) had neighbourhoods close to downtown that avoided overly devastating population loss and have at least moderate incomes. St Louis experienced population loss in its core neighbourhoods that is more comparable to Detroit, but household incomes remained moderate in the South Side, where much of the population loss was likely related to declines in household sizes. The presence of these neighbourhoods that have retained some vitality helps support downtown of these cities.
On the other hand, Detroit's downtown-midtown core is disconnected from most of the rest of the city by large swaths of largely abandonned neighbourhoods***. This may make it difficult to take advantage of the nation-wide trend of revitalization of urban cores with less housing available for renovation and fewer neighbourhoods that have sufficient critical mass to revitalize.
Outer neighbourhoods, which are relatively suburban in character, are unlikely to appeal the demographic that is attracted to urban cores. In other cities, continuity between the urban core and outer neighbourhoods may lead to interaction, and spreading of a relative degree of prosperity to the outer neighbourhoods. However, in Detroit, they are disconnected from the core by largely abandonned neighbourhoods, limitting potential interaction. With high poverty, crime and low education levels, combined with little to none of the advantages of urban neighbourhoods and being disconnected from the core, it will be more difficult than in other cities to prevent these outer neighbourhoods from continuing to decline and becoming abandonned like more close in neighbourhoods.
If these outer neighbourhoods continue to decline, and the core experiences only moderate growth, it will strain Detroit's budget and hinder the city's recovery further.
As for the other cities, Pittsburgh appears to have stabilized much of its neighbourhoods and maintained the cohesiveness of the city, leading to substantial potential for recovery from urban decline. St Louis may soon follow as its core is experiencing substantial revitalization and recent decline has mostly been limitted to the North side. Buffalo's downtown is not revitalizing as much, but recent decline is mostly limitted to the East side so it could foreseeably begin to recover as well. The situation in Cleveland is more difficult, while overall post-WWII losses have been comparable to the other 4 cities, it has been losing population at a greater rate than St Louis, Pittsburgh and Buffalo in the last decade. The situation appears somewhat complicated and could take a while to sort itself out and stabilize. For instance, the greatest population losses have been in the East side, where there are neighbourhoods with substantial income increases adjacent to some with substantial decreases.
*The range is 17,357 for Boyton-Oakwood Heights in Detroit to 199,245 for Cleveland's West side for 1950, and the 2010 range is 2,783 for Delray in Detroit and 90,413 for Cleveland's West side
**Toronto's urban neighbourhoods that saw little new construction (or destruction) since 1950 saw a population decline of about 30%, in Montreal it was about 50% or close, although I'm assuming the decrease in household sizes in Montreal was greater than in most cities.
***Even these neighbourhoods are not completely abandonned, and will have a scattering of houses here and there, and even several blocks with little to no vacant lots/homes. Even if they're only 1/2 abandonned though, I think that could still be enough to cause Detroit's core to be disconnected from outer neighbourhoods.