In "Earning the Rockies," Robert D. Kaplan explores the shifting dynamics of social classes in America. He points out that the middle class has been eroding over time, transitioning into a precarious working class that is increasingly at risk of falling into poverty. This shift highlights the economic struggles faced by many, emphasizing the vulnerabilities of those who once enjoyed stability.

Moreover, Kaplan notes the emergence of a more privileged upper-middle class that aligns with a global elite. This widening gap between socioeconomic classes reflects broader changes in society and economy, suggesting a growing divide that could impact America's future. The book encourages readers to consider how geography influences these developments and the implications for the nation's role in the world.