Return on capital below economic growth rate?

Today I saw a chart

The main idea is that if the return on capital is lower than economic growth, big problems will occur.

This is a screenshot from a macro strategy report by Guojin Securities, titled “We Are 100 Basis Points Away from a World War”, which uses the r-g (return on capital minus economic growth) indicator to analyze global distribution conflicts and systemic risks.
Underlying explanation:
Low asset returns hinder young people’s upward wealth mobility, because capital is no longer scarce.
The report attributes this to “China’s national capitalism being too successful over the past 40 years,” claiming China’s capital accumulation has greatly changed the global capital supply and demand landscape.
This analysis is based on the core idea from Thomas Piketty’s Capital in the Twenty-First Century:
r > g: When the return on capital exceeds economic growth, wealth naturally concentrates among capital owners, widening the wealth gap.
r ≈ g or r < g: Capital accumulation slows down, distribution conflicts intensify, and social stability decreases.
The report views an r-g close to zero as a “world war-level” risk warning, with 100 basis points (1 percentage point) being the current gap from zero.

1. Core logic: What is r-g?
   r (Return on Capital): The return rate on capital (money, stocks, real estate).
   g (Economic Growth): The overall society’s economic growth rate (i.e., income growth).
   Normal situation: Usually r > g. This means “money making money” grows faster than “people working,” leading to the rich getting richer and widening the wealth gap.
   In the chart: the state where (r-g ≈ 0): capital is no longer profitable. When the return on capital even fails to outpace GDP growth, the era of “making money while lying down” ends, and asset prices lose support.
2. What crisis does this state indicate?
   Social class solidification (young people have no way out)
   When asset returns are low, the overall “cake” of society is still growing, but the wealth doesn’t go to capital holders. Young people find it hard to increase wealth through investment, and low capital returns lead to poor corporate profits and stagnant wages.
   In the chart: this explains why the “May 1968 French protests” (a global youth movement) occurred, as well as current worldwide populism and anti-globalization sentiments. Wealth inequality hasn’t shrunk, but young people feel “the upward mobility channel is blocked.”
   Risk of asset bubble burst
   Asset prices (stocks, bonds) are priced based on future returns. If long-term r-g remains low, it means future cash flows are heavily discounted, and current asset prices may be overvalued, facing potential corrections at any time.
   Reshaping the global capital landscape
   The report attributes this phenomenon to “China’s national capitalism being too successful,” meaning China, as a huge economy, has joined the global system by providing大量廉价且高效的资本 / 商品，导致全球资本不再稀缺（资本过剩），从而压低了全球的 r-g。

So what if the return on capital is low? It’s already very low now, so what?
But I asked for a long time why Doubao (a nickname) couldn’t convince me either.