The median black person is significantly poorer than the median white person, and with that comes a variety of factors that can impact education and test scores.
Schools are more likely to be underfunded and overcrowded. Neighborhoods are more likely to suffer from crime, drugs, and unemployment. Children are more likely to be hungrier, more sleep-deprived, and have less access to books and computer learning time.
There's also the family environment to consider. Poverty and financial struggles makes parents more stressed, which makes them less focused and engaged with their children. Black children are also more likely to be raised by single mothers or grandparents and may not have enough quality time with adults to teach and mentor them.
Hispanics and Native Americans suffer similarly as a result of poverty.
These struggles compound over years and over generations, which would make it hard for poorer minorities to catch up. Statistically speaking, minority households face more hurdles than white households, and that spills over into children's academic success.
There is evidence of racial differences in IQ narrowing when economic conditions for black communities improved, so it's not a stretch to say that given enough improvement over time, things like IQ gaps and test scores can become negligible.
There's also evidence that IQ scores are bogus and designed to emphasize knowledge taught in segregated white schools, which would naturally put all other races at a disadvantage.
Regardless of whether there is a genetic component or not, environmental factors do play a significant role and if we value intelligence and education across all races, it would benefit society as a whole to improve the environment for underserved communities and let time tell whether or not we can help it
