Vague Definitions & Uncertain Status​
The “middle class,” defined by over 100 criteria (income, assets, education, etc.), lacks a clear global standard. Even by income—often set at 66%-200% of median—it varies widely. Examples: 60% of Japanese (1970s) and 70% of South Koreans (1980s) self-identified as middle class during booms, but post-2008, only 40% of Koreans did (stats showed ~60%). Universally, middle-class individuals typically achieve upward mobility via education and effort, enjoy higher incomes, and live in cities—but are “fragile,” burdened by debt and job insecurity.

Long-Term Decline & Widening Gaps​
Globally, the middle class is shrinking. In the US, their share fell from 61% (1971) to 51% (2023); Japan transformed from a middle-class society to an “M-shaped” one post-1990s bubble. A 2019 OECD report noted middle-class income share dropped from 65% (1980s) to 54% (2024) in France, with inequality within the class worsening (top 10% earn 3.2x bottom 10%, up from 2.4x in 2000s). Developing nations (e.g., China) see expansion in numbers but face precariousness due to housing, education, and healthcare costs.

Root Causes: Economic Shifts & Asset Volatility​
Middle-class instability stems from economic changes: deindustrialization (US lost 26% of manufacturing jobs since 1970s), globalization (jobs shifting to low-cost regions), and the “dual labor market” (high-paying “good jobs” vs. insecure “bad jobs”). Asset reliance (real estate, stocks, education) backfires—property and stock market declines, “credential inflation,” and financialization reduce resilience. Post-2008, QE helped the wealthy but hurt the middle class.

Mindset Traps & Internal Pressures​
Middle-class anxiety is also self-inflicted. As described in Korea, many inflate standards by emulating the wealthy—buying luxury/knockoffs, indulging in “conspicuous consumption” (organic food, fitness), and competing in costly private education for kids. Six common traps (e.g., excessive education spending, high mortgages) drain finances. Experts urge mindset reform: rethinking budgets, cutting unnecessary expenses, and adapting to economic realities.

Bottom Line​
From shrinking numbers to fragile stability, the global middle class faces external pressures (economic shifts) and internal traps (overconsumption), threatening its traditional role as a societal anchor.