There are many less educated parents in this world who do not speak to their children enough in the most critical years, ages 1-3, leaving their children to play catch up with their peers (in vocabulary & other areas) in Kindergarten and grade school, if they'll even be able to catch up at all.
There are less educated parents who use electronic devices to babysit (via games, cartoons, music videos, movies, etc.) their children rather than taking their children to a museum, an aquarium, a library, or to historic monuments to LEARN something rather than to distract their child's attention and "keep them quiet."
There are less educated parents who refuse to encourage and support their children's education by not engaging the child, praising the child's progress, visiting the child's teachers, physically going to see the child in school activities such as sports, music, theater, etc.
This is not to say that all less educated parents do these things but I have seen it quite often enough to know and understand the harmful consequences. I've also seen the vast differences that some affluent parents exhibit that boost their child's understanding, productivity, creativity, potential, and success in school and beyond.