You don't have to be rich to give attention to your kids.
My parents were never rich, I am not rich, yet I have a high IQ as do my kids, one of which is mixed race with one of these 'minority cultures'. I was always prompted by teachers to take more advanced and gifted classes because the class couldn't keep up. I finished with a US-equivalent college-level education before my 19th birthday. I have a friend who is Hispanic in the US, finished with a bachelors at 16yo.
The problem is that these 'minority' parents aren't speaking English correctly themselves or don't do math correctly themselves. I'm not talking about immigrants, I'm talking about people that have lived in the US for several generations. The problem is not with the culture at the school, it's with the culture in these groups. They feel entitled to get these benefits, then they have to put the effort in it to get them. Speak correct English at home, don't engage with other parents or family that puts people down for 'acting white' or trying to achieve something outside their own culture. Heck, look at some of the comments Neil deGrasse Tyson has made on his own venture into science, his peers were pressuring him to do more for his 'community' as well and leave astrophysics.
Since the 60's there has been a lot of time and effort wasted on these communities and brilliant people have probably given in to the pressure within those communities to not do the best they can. When proper English isn't even understood in schools, you have a problem, not a school problem but a community problem.