Lately I've been enjoying a hobby of quickly researching hypotheses and arguments I find interesting with Deep Research, then organizing the output. NotebookLM's new slide generation feature has accelerated this hobby a bit, and I've decided to start publishing some of the content I find compelling.

I'd come across two related theories: one arguing that Japan's large middle class was formed because manufacturing — a high-average-wage industry — was the central industry; and another arguing that when a service industry (rather than manufacturing) becomes the core industry driving GDP growth, wage gaps widen and social inequality follows. I researched these arguments and organized them into a brief summary.

Key Takeaways

  • Manufacturing was an industry that easily raised labor productivity per person through mechanization, which in turn pushed up average wages.
  • Factories invented ways to increase output without increasing working hours by introducing sophisticated machinery.
  • The spring wage negotiations (shunto) conducted in key industries like manufacturing set a "wage increase benchmark" that rippled across the entire national economy, functioning as an anchor that promoted redistribution.
  • Service industries, by contrast, are labor-intensive and struggle to improve labor productivity, making wages stagnant — a phenomenon known as "Baumol's cost disease."
  • Advances in IT have driven a polarization between "high-skill" and "low-skill" workers, leading to a bifurcation in employment.
  • Since the 1980s, the share of workers employed in manufacturing fell from 25% to 16% by 2020, and the Gini coefficient — a measure of income inequality before redistribution — has risen consistently in parallel.
  • These trends suggest that society could not adapt as it shifted away from a model centered on "manufacturing, full-time employment, and a single-income household."
  • This is not unique to Japan — developed countries that have seen declines in their manufacturing share have experienced similar patterns. Germany, which maintained manufacturing as a matter of national policy, kept its middle class robust by contrast.
  • The current challenge is: "In a service-centered economy, how do we optimize redistribution and close inequality gaps?" — and in theory, this is achievable.