Public school teacher here.
The US system is almost singularly (I'd argue myopically) focused on improving outcomes for at-risk students.
Title 1 of the 1965 Elementary and Secondary Education Act: ESEA was explicitly a civil rights law, and title 1 provides grants earmarked for schools with high percentages of low-income students. Being a "title 1 school" means you're oftentimes better funded than the wealthier school on the other side of the tracks. In my well-off school, we'd love to have a 1-to-1 ratio of students to laptops but we can't afford it. Meanwhile,many of our neighboring rural systems implemented such a system years ago.
Since 2001, the school reform movement has aggressively implemented policies designed to close the white/black, rich/poor achievement gaps. Note: I actually hate most of these reforms but their intent is undeniably noble.
No Child Left Behind (2001): standardized testing was the centerpiece of NCLB because it would shine light on under-served demographics. Previously schools would be measured by SAT or college admittance-- metrics that completely ignored at-risk kids. With NCLB, every state had to test every kid, and systems had to report proficiency rates broken down into ethnic and economic subgroups. Before NCLB, a school that enriched its high fliers would look great on paper. After NCLB, if a school couldn't get all of its subgroups to show adequate yearly progress year-over-year, the school was at risk of being taken over by the state and all of its faculty dismissed. The practical effect of NCLB was for schools to focus entirely on pushing low-performing students over the proficiency hump-- often to the detriment of higher-performing (rich) students.
Charter Schools: look at the biggest charter school networks (Success or KIPP, for instance)-- they're all targeting at-risk populations in big cities and working hard to improve outcomes. One of the reasons they're able to do what they do is because they're generally better funded than their traditional counterparts thanks in large part to philanthropy. You'll often hear school choice advocates point out that they're only trying to provide the poor with the same choices that the rich already have available to them
Race to the Top (2009): the centerpiece of this competitive grant system was to attach teacher evaluations to "value-added" modeling (VAM), i.e. formulas that compared expected student performance to actual student performance, thus measuring a teacher's impact on scores. Most states adopted systems that broke VAM data into achievement groups, placing an emphasis on "adding value" to low-achievers' scores.
I could go on, but if you think our system is designed to benefit the rich at the expense of the poor, you should teach for a year and report back.