Inside the island fortress of America's mega-billionaires

[orthoclad]

6. When you're dividing up 115 Trillion dollars

into VERY unequal slices, that bottom scale (50%) is hard to fit in, since the bottom half holds only 2% of the wealth.

The graph is most useful for showing the change in wealth division over time.

I'm not sure which line you are calling the "brown line", but that black color barely visible at the bottom is the majority of people - the ones feeding the plutocrats on the OP's island. I'd love to see the graph broken down into smaller slices, like the top 1% and the top 0.01%. According to the study, the top 1% held 1/3 of the total family wealth, or 38 TRILLION DOLLARS. Compare that to the bottom half, which does the work but holds only 2% of the wealth.

Here's the original study:
https://www.cbo.gov/publication/58533

and here's some of the executive summary, bold mine:

Total Wealth. The total real wealth (that is, wealth adjusted to remove the effects of inflation) held by families in the United States tripled from 1989 to 2019—from $38 trillion in 2019 dollars (roughly four times the nation’s gross domestic product, or GDP) to $115 trillion (about five times GDP).
Concentration of Wealth. The growth of real wealth over the past three decades was not uniform: Family wealth increased more in the top half of the distribution than in the bottom half. Families in the top 10 percent and in the top 1 percent of the distribution, in particular, saw their share of total wealth rise over the period. In 2019, families in the top 10 percent of the distribution held 72 percent of total wealth, and families in the top 1 percent of the distribution held more than one-third; families in the bottom half of the distribution held only 2 percent of total wealth.
Trends by Family Characteristics. Over the 30-year period, the median wealth of families in higher-income groups, families with more education, and older families rose faster than that of families with less income, families with less education, and younger families. The median wealth of White families exceeded that of families in other racial and ethnic groups by considerable amounts throughout the period. The median wealth of every cohort born since 1950 was less than the preceding cohort’s median wealth when that cohort was the same age.
Trends Since 2019. In the first quarter of 2020, total family wealth declined as a result of the disruption in economic activities caused by the coronavirus pandemic. By the end of the second quarter of 2020, total family wealth had recovered; it continued to increase through the fourth quarter of 2021 but declined slightly in the first quarter of 2022.