Education had much to do with the rise of blacks. As of 1940, black adults averaged just 5 years of schooling. By 1960 that was 8 years and by 1970 it was 10 years. Obviously, doubling your education within one generation tends to increase your income, regardless of which party is in power or what policies they follow. In our own high-tech era, education is even more important.
Nothing is more of a handicap to blacks today than inadequate education.
There are many reasons for these inadequacies. Democrats are too completely dependent on the teachers' unions to be able to break the public school monopoly or to get rid of incompetent teachers or even to insist on the teaching of the basics, instead of the dumbed down education and amateur social engineering that the education establishment likes. Whatever political support there is for vouchers has come almost exclusively from Republicans. Another factor in the decline of American education in general and education in low-income minority communities in particular, is the difficulty of either punishing or expelling disruptive and violent students who destroy the education of the other students. Liberal judges have made it literally a federal case when schools crack down on disruptive and violent students.