You're right about good parenting being a bad term. However, it is the qualities (value neutral) of the parenting that determines outcome rather than the richness of the environment. To quote Paul Tough, who gives a good summary of the research:
"The disadvantages that poverty imposes on children aren't primarily about material goods. True, every poor child would benefit from having more books in his home and more nutritious food to eat (and money certainly makes it easier to carry out a program of concerted cultivation). But the real advantages that middle-class children gain come from more elusive processes: the language that their parents use, the attitudes toward life that they convey. However you measure child-rearing, middle-class parents tend to do it differently than poor parents; and the path they follow in turn tends to give their children an array of advantages. As Lareau points out, kids from poor families might be nicer, they might be happier, they might be more polite; but in countless ways, the manner in which they are raised puts them at a disadvantage in the measures that count in contemporary American society."
"The disadvantages that poverty imposes on children aren't primarily about material goods. True, every poor child would benefit from having more books in his home and more nutritious food to eat (and money certainly makes it easier to carry out a program of concerted cultivation). But the real advantages that middle-class children gain come from more elusive processes: the language that their parents use, the attitudes toward life that they convey. However you measure child-rearing, middle-class parents tend to do it differently than poor parents; and the path they follow in turn tends to give their children an array of advantages. As Lareau points out, kids from poor families might be nicer, they might be happier, they might be more polite; but in countless ways, the manner in which they are raised puts them at a disadvantage in the measures that count in contemporary American society."