I don't think affirmative action is a MISTAKE, but I do agree with your point. There's no denying that it doesn't address the underlying problems.

Education is, of course, vitally important, but that's one reason why scholarships which preferentially select for black students exist. The playing field isn't level, so some admittedly cumbersome solutions are necessary.

Even if we took it all the way back to primary schools, what (I think) you're suggesting would mean funnelling extra money and/or resources to black students/schools, which would be a form of affirmative action.

There's no single "silver bullet" that wil solve all of the problems resulting from the history of black people in America. Education, affirmative action, cultural shifts, all of them and more form part of the picture.