There are obviously many factors in play here, racism is one obvious factor, education is another major problem since public education is predominantly funded via local property taxes, this produces areas with good schools and high property values and areas with poor schools and low property values. Instead of education being a tool for lifting people up, it’s a mechanism to further entrench existing wealth and classes, reducing social mobility. Another major factor is the rise of the prison industrial complex, with private prisons becoming big business. This has created perverse incentives to lock up as many people as possible to generate very cheap labor. The result of these perverse incentives is that we have lawmakers being encouraged to get tough on crime, and this has a hugely disproportionate affect on racial minorities in America. See the school-to-prison pipeline.