Since the pandemic, research has demonstrated that the earnings gap between the rich and the poor in America has narrowed. This is mainly based on the tight labor market post-pandemic, as competition for low wage workers has increased. As a result, wage gains have accrued at a higher quantity for low-income workers compared to higher-income workers. These gains are concentrated in the younger demographic of the labor market though, due to young workers' increased tendency to switch jobs.
See "Post-pandemic, research shows low wage workers in the US have seen wage gains ", Justin Lahart, Wall Street Journal, March 6, 2023