Final answer:
The decline of blue-collar work is associated with the postindustrial age, which shifted economies from heavy industry to services and information-driven sectors.
Step-by-step explanation:
The decline of blue-collar work is most commonly associated with the postindustrial age. During this period, economies in developed nations shifted from heavy industry to services and information, leading to a decrease in factory and manual labor jobs. Mechanization, automation, and outsourcing of manufacturing jobs to other countries have all contributed to this decline. Additionally, there has been a significant rise in the importance of information, as those able to produce, store, and transmit information have taken leadership positions in society. This transformation has greatly impacted not only the economic structure but also the way people work and live in modern society.