Obviously there are many factors at play. But it boils down to economics. Both in the micro sense of household finance, and the macro scale of economic opportunity.
The compound effects of generational wealth and institutional racism explain why it's so different for blacks and whites in this country.
In economics terms, that means Blacks are crippled at the micro scale of household finance, and experience a less hospitable climate in the economy at large.
Disparities in Wealth by Race and Ethnicity in the 2019 Survey of Consumer Finances
www.federalreserve.gov
By some estimates bequests and transfers account for at least half of aggregate wealth (Gale and Scholz 1994), have recently averaged 3 percent of total household disposable personal income (Feiveson and Sabelhaus 2018), and account for more of the racial wealth gap than any other demographic or socioeconomic indicator (Hamilton and Darrity 2010).8 In addition to direct transfers or gifts, families can make investments in their children that indirectly increase their wealth. For example, families can invest in their children's educational success by paying for college or private schools, which can in turn increase their children's ability to accumulate wealth. For these reasons, wealth (or a lack thereof) can persist across generations and reflect, among other factors, a legacy of discrimination or unequal treatment in housing, education, and labor markets.9
One reason wealth-holding is relatively high among White families is they are considerably more likely to have received an inheritance or gift. Another reason is White families report other indicators associated with higher levels of family support (Table 2). For example, nearly 30 percent of White families report having received an inheritance or gift, compared to about 10 percent of Black families, 7 percent of Hispanic families, and 18 percent of other families. Conditional upon receiving an inheritance or gift, White families also tend to receive larger inheritances.