Final answer:
Detroit is the city that has experienced the most severe decline since the 1970s, evidenced by massive population loss, economic downturn, and the transformation from a Manufacturing Belt to the 'Rust Belt.'
Step-by-step explanation:
Among the cities in the old economic core that has experienced the most severe decline since the 1970s, Detroit stands out as an extreme case. The city, once a booming industrial hub with its thriving auto manufacturing industry, has seen a drastic decrease in population and economic activity.
The Rust Belt, a term that became synonymous with economic decline, describes the region where cities like Detroit, Cleveland, and others have faced significant challenges due to deindustrialization. Factors such as factory closures, job losses in manufacturing, and a shift of industry to regions with lower labor costs or overseas, have contributed to the decline.
Municipal governments struggled with declining tax revenues, and some cities, such as New York City, faced near bankruptcy. However, New York's case is not as severe when compared to Detroit, which lost 61 percent of its population since 1950 and encountered a 25 percent decrease in population from 2000 to 2010 alone. The stark decline of Detroit is indicative of the transformation from a 'Manufacturing Belt' to the 'Rust Belt.'