If the quoted statement were true, the above log-log scatterplot of GDP per capita in 1950 vs gdp per capita in 2016 would have a trendline slope less than 1. But in actuality it has a trendline slope far greater than 1. This means that the countries that were already above average in 1950 grew faster in percentage terms than the countries that were below average in 1950. China's fast catch-up growth is the exception, not the rule. It's an anomaly caused by anomalously high IQ in global terms, plus the sudden removal of factors that were holding them back earlier (civil war, communism, lack of free trade). Ordinarily, whatever qualities made a country have good economic growth pre-1950 would have made it more likely to have good economic growth from 1950-2016, and whatever factors made a country have poor economic growth pre-1950 would have also made it more likely to have poor economic growth from 1950-2016. These factors are likely to include IQ, economic policy, rule of law, and proximity/access to wealthy trading partners.
"economies usually have a period of impressive catch-up growth as they develop, then stagnate as they near the technological frontier."
FACT CHECK: This is literally the opposite of what's been observed empirically.
https://ourworldindata.org/economic-growth-since-1950
If the quoted statement were true, the above log-log scatterplot of GDP per capita in 1950 vs gdp per capita in 2016 would have a trendline slope less than 1. But in actuality it has a trendline slope far greater than 1. This means that the countries that were already above average in 1950 grew faster in percentage terms than the countries that were below average in 1950. China's fast catch-up growth is the exception, not the rule. It's an anomaly caused by anomalously high IQ in global terms, plus the sudden removal of factors that were holding them back earlier (civil war, communism, lack of free trade). Ordinarily, whatever qualities made a country have good economic growth pre-1950 would have made it more likely to have good economic growth from 1950-2016, and whatever factors made a country have poor economic growth pre-1950 would have also made it more likely to have poor economic growth from 1950-2016. These factors are likely to include IQ, economic policy, rule of law, and proximity/access to wealthy trading partners.