Important to note also that "tend to equalize" can just as easily mean "the top comes down at the same time the bottom goes up" as "the bottom rises faster than

Important to note also that "tend to equalize" can just as easily mean "the top comes down at the same time the bottom goes up" as "the bottom rises faster than the top". By most big measures, the world is more equal than it was 30 years ago, but that came at the cost of stagnating a significant chunk of the global "top" (ex. the US middle class).