This article wonders why the rich are getting richer and the answer is compound interest. Having $1 million in the bank will reliably generate between $25k and $50k per year. Having $2 million in the bank will reliably generate between $50k and $100k per year. Having $3 million in the bank will reliably generate between $100k and $150k per year. So someone with $3 million in savings and still working their 200k job w…
But that phrase is actually talking about the type of comparison where you have a look at, say, the top 1% of earners, and compare their income to the bottom 50%. We see that the ratio of the average earnings of the two groups is swaying to in favour of the top 1%. That is not nearly such an obvious result. Rich people die, they split up their fortune to give to their children, which should help level things out, but no, we still see that segment of society getting steadily richer faster than anyone else.
Another way of looking at it would be to compare velocity to acceleration. You are talking about the rich having a bigger velocity increase for the same acceleration increase, which is true. But the phrase "the rich are getting richer" is actually talking about the fact that the acceleration is actually higher for the rich - they can get a 10% increase in wealth per year, were as a middle-class person might only get 3% for their tiny investment.