They do leave out some things: food + shelter. Many poor students have problems with nutrition and safe shelter, both of which make learning near impossible.
The metro area I'm in is a perfect example of this. We have two small cities side by side. Pretty much the same socioeconomic makeup in both. One invests massively into education, tutoring, summer programs, etc. In the other the schools are literally crumbling, but hey, the police budget is at an all time high! The city investing into education ranks 9/10-10/10 on state tests, the city that allows its buildings to literally crumble (the library was off limits for a while because the ceiling tiles were falling so often they were injuring the children), ranks 2/10.
We don't need to dumb down anything. We need to raise everyone up by investing in education.