In reply to your edited post:
Even after the New Deal and War on Poverty by LBJ, reactionary white voters turned the tide by the end of the 1960's led to the rise of Nixon and Reagan. Moreover, it led to triangulaters like Clinton. Your idealistic version of the 20th century doesn't really hold true.
Black President, two Black Secretary of States, Black Attorney General, Black Senators and Governors and 40+ Black US Reps.
Explain to some Southern Black sharecropper in the 1930s that that's going to be the situation in his kid's lifetime "but nothing really changed".
Repubs trying to roll back voting rights, but ignore that voting rights are FAR better than they were before 1965. Southern voting access has gone from like 5% to 90%.
Way more work needs to be done in education, but ignore that the % of the Black population with a high school diploma has gone from 25% to 80% in the last 50 years. And college graduation rates are far higher than ever before.
More work needs to be done in health care, but Obama's health care act has more Black families covered than before.
More work needs to be done in jobs, but the median income of the Black family continues to increase, and its far ahead of where it was in the pre-New Deal days.
More work needs to be done in the criminal justice system (that's probably been the most regressive part in recent decades), but even Southern states have been passing criminal justice reform left and right as we speak, because they don't want to pay millions of dollars for new prisons anymore. You even have Republican presidential candidates calling for fair sentencing laws. Can you imagine the laughs that would have gotten 50 years ago?
I ain't saying that we've reached the mountaintop. But to act like the works of the past didn't lead to progress is ridiculous. We're doing WAY better at this than we were when our granddaddies were born.