The main reason they can't go to the root cause is because it touches on the big cornerstone of security. That area is the exclusive domain of what some would call the "deep state" but in reality is just the FBI along with police cartels and the prison/law/policing oligarchs.
Poverty alone doesn't cause kids to fail development. IIRC some studies in the past pointed out that adjusted for inflation, the wages in mainland China for blue collar workers were equally low as those for American ones. Yet the former don't struggle as a group to create good results.
What causes kids to suffer is when poverty leads to crime, or neighborhoods are filled with violence. When kids grow up among drug dealers, see and hear guns constantly fired in anger in their environment, when they have to deal with addicts in their own household, they don't have time for trivial pursuits like developing their resume in preparation for university. They have to focus everything on survival.
These kids are mostly not stupid by birth. It takes a tremendous amount of both emotional and actual intelligence to navigate such dangerous situations, not to mention maturity.
But it will all be applied into the wrong areas that won't help give them good scores nor land them in comfortable jobs.
Actually if you have read some of the stories about Chinese minorities in for example Britain, like those rioters where many were university students and they don't know how to cook, don't know how to get groceries for themselves and can't hold down the most basic jobs, you see that there are just as many retards in China as there are in America. It's just how you channel them into not falling off a steep cliff and so they can still perform useful functions.
Any country that has functioning nutritional status and doesn't have endemic levels of drug abuse is gonna have roughly equal populations in terms of intelligence. As long as the children aren't stunted by above named factors, all colors of humans have the exact same development potential.