You could note that, for instance, despite having a lower-than-average cost of living for the west(^1,2) and lower-than-average taxes for the west (^3,4), the US is top-five for both average wage (^5,6) and PPP-adjusted median income (^7,8). And despite what you may think, even adjusting for government transfers (e.g. healthcare) does not tilt the scale: the US boasts a #1 (or #3, depending on who you ask) PPP-adjusted disposable income (^9). These generally apply to medians too, so one cannot even fall back on skew to explain it away.
Meanwhile, when we speak of "inequality" and billionaires, China has above-average taxes (seems to be 25% across the board with no carve-out for capital gains), yet has far worse inequality than the US.
As with most things economic, reports like this can be crafted to fit whatever narrative you like. But if you are sitting in the US in 2021-- one of the wealthiest societies in human history-- and complaining about how bad capitalism or low taxes are, you're badly misinformed about the "normal" economic state of a human and where you sit. Here's a hint: it's probably in the 95th percentile across history and the 90th percentile today.
Sources:
Cost of Living
1. https://www.numbeo.com/cost-of-living/rankings_by_country.js...
2. https://www.worlddata.info/cost-of-living.php
Taxes
3. https://tradingeconomics.com/country-list/personal-income-ta...
4. https://stats.oecd.org/Index.aspx?DataSetCode=TABLE_I6
Average wage
5. https://worldpopulationreview.com/country-rankings/median-in...
6. https://en.wikipedia.org/wiki/Median_income
PPP-adjusted Median income
7. https://statisticstimes.com/economy/countries-by-gdp-capita-...
8. https://en.wikipedia.org/wiki/List_of_countries_by_average_w...
PPP-adjusted Disposable household income
9. https://en.wikipedia.org/wiki/Disposable_household_and_per_c...