Recently, I came across a rather straightforward article on HN titled "We were wrong about convergence." It was quite interesting, discussing a foundational theory (the Solow–Swan growth model) that was once questioned by the economics community, later widely accepted, but is now being overturned by reality: Do poor countries truly grow faster than rich ones?

For a long time, many believed this question had been answered. Especially from the late 20th century to around 2010, global data once showed that the average growth rate of developing countries was indeed faster than that of developed countries. However, the latest data indicates that this trend has not persisted and may even have reversed.

Behind this lies an intuition we take for granted but may have misunderstood from the very beginning.

Why We Naturally Believe "Poorer Places Are Easier to Develop"

From a young age, we are repeatedly taught a seemingly reasonable judgment: if a place is poor, it has greater room for development; a low starting point makes it easier to grow faster. China's rapid development is often explained this way—its low starting point is seen as almost a "necessary condition" for its subsequent high-speed growth.

This logic is easy to accept because it "seems plausible" in many scenarios. Whether for individuals, businesses, or regions, a thin person trying to gain weight will naturally see a faster and easier increase compared to an already overweight person.

However, the problem is that if "the poorer, the faster" were a stable economic law, most poor countries in the world should have already caught up. Yet reality is quite the opposite. Many countries remain stuck in low-growth states for extended periods, unable to even achieve stable growth.

This shows that a low starting point does not automatically translate into growth momentum. It can signify potential, but it can also imply structural constraints. Simplifying China's development experience as "fast because it was poor" essentially confuses the result with the cause.

What Made the Theory Seem Valid Was the China Variable

So why did we once believe that the theory of "the poorer, the faster growth" was accurate? The answer is not complicated: during that period, an extremely important variable was overlooked—China.

From the mid-to-late 1990s to around 2010, China entered a phase of rapid industrialization and urbanization, leading to a sharp increase in demand for commodities. Prices of iron ore, oil, soybeans, copper, and other goods were systematically driven up, providing unprecedented growth momentum for a group of resource-exporting countries.

Take Brazil as an example. From 1980 to 1995, Brazil's average annual growth rate in real per capita GDP was only 0.1%, almost negligible, with long-term economic stagnation often referred to as "Latin Americanization." However, between 1995 and 2010, driven by China's explosive demand for soybeans, iron ore, and oil, Brazil's per capita GDP grew at an average annual rate of 1.9%. Clearly, during this period, Brazil did not undergo institutional leaps or productivity revolutions; it merely benefited from the spillover effects of China's economic expansion.

In other words, the "high-speed growth" of many developing countries during that time was more like a result of being propelled by China, the world's largest variable. As China's growth slowed and global commodity prices retreated, this external pull disappeared, and growth receded accordingly. Thus, the economic judgment once thought to be "verified by data" began to appear less reliable.

The Shift in Growth Rates Between Rich and Poor Regions Is Also Felt Within Economies

Zooming in from the global perspective to the domestic level, this structural relationship remains clear. Take Guangdong as an example. In recent years, Shenzhen has continued to be one of the most stable and resilient growth engines in the province. Both its economic output and actual growth rate have been significantly higher than the average. In 2025, Shenzhen alone accounted for half of Guangdong's GDP growth.

If we view Guangdong as a unified economy, we can draw an intuitive but not entirely rigorous analogy: the Pearl River Delta resembles the urban core, while eastern, western, and northern Guangdong are more like the suburbs.

The relationship between the city and its suburbs is not one-directional but operates on different time scales. In a relatively market-oriented environment, when the city develops rapidly, capital, talent, and industries naturally concentrate in the city, continuously drawing resources away from the suburbs, which then appear to grow more slowly. Conversely, when the city's development slows, its structural pressures rise rapidly, and it becomes more reliant on the suburbs' land, labor, and fiscal space to sustain itself.

From an operational perspective, this relationship is constantly shifting. It is neither a one-sided "exploitation" of the suburbs by the city nor a one-sided "support" of the city by the suburbs. However, from a long-term developmental perspective, one thing is relatively certain: whether the suburbs can be genuinely driven depends on whether the city possesses the capacity for sustained expansion. Only when the city itself grows rapidly can new demand, industries, and tax bases spill over to the suburbs. If the city lacks momentum, no amount of emphasis on balanced distribution can significantly alter the overall pace.

In other words, the entire vehicle can only accelerate if the engine runs fast. If the engine itself lacks power, no matter how the fuel is distributed, the vehicle won't move.

Shenzhen's role in Guangdong is similar to China's role in the global economy over the past two decades. Growth has never been about being "poorer" but about the ability to continuously generate demand, absorb resources, and form a self-sustaining cycle.

The question is, if it is indeed the case now, as it was from the 1960s to the 1990s, that "poorer regions grow more slowly," what does this mean for ordinary people living in such regions?