Gary Becker’s answer:
Why did the progress of blacks stop well short of achieving full equality with whites, and is the slowdown during the past 20 years in black progress only temporary, or is it an indication of what the racial situation will be during the next few decades? The sharp slowdown is surprising mainly because institutionalized and personal discrimination against African-Americans has continued to fall into this century. Probably the most important offset to the decline in discrimination is the rapid growth since the 1960’s in the fraction of black children raised in households with only one or no parents-these households also grew among whites, but at a much slower pace. Moreover, white single parent households mainly arise from a divorce between parents who had their children while married (or while living together), whereas never-married and quite young mothers raise many black children.
In addition, there is social pressure on young blacks growing up in segregated neighborhoods to engage in crime, including selling drugs, and to not “act white”, where acting white sometime is taken to mean studying hard and investing in one’s human capital. These pressures act more on black boys rather than girls, which help explain why the achievements of black women are much closer to those of white women than is the gap between black and white men.
It is too early to tell whether these and other forces that have prevented blacks from achieving full parity with whites are temporary or more long lasting. A disturbing fact is that growing up in families that invest less in their children casts a long shadow since children brought up in these families tend also to invest less in their children. This process gets to be repeated to some degree over subsequent generations.
This is one of the reasons why I am not a liberal. The problems of poverty today are not discriminatory in nature, they tend to be cultural and family related, problems that are far better addressed on the right than on the left. Arnold Kling has more here.