The people I work with have this attitude that 300k/year is expected (aka middle class) from a two income family. IMO, DNA has little impact on Black achievement, rather culture is "crushing" black America. When 80% of any population is not playing the game they hold the average hostage.
My personal theory is you tend to measure yourself in comparison the well to do people around you. If you fail to reach that level you are more likely to push your children up a notch. However, everyone needs to balance success vs. personal sacrifices and needs to decide when enough is enough.