The numbers are similar at other top schools, and feed into everything beyond, including startups.
1: https://www.nytimes.com/interactive/projects/college-mobilit...
There's no data in the article about the income level of the students applying. Are there 15 times as many wealthy applicants? Disparity is often contextualized in terms of systems of oppression and discrimination. Individual behavior, influenced by the effect being poor has psychologically, is likely to contribute to the difference in economic diversity.
Still, your claim that nobody cares about the poor is not justified. Also, there are many just causes, and we can work on all of them in parallel.
The groups I was talking about, the ones that "nobody cares about" might not come to mind immediately, precisely because one rarely hears about them, but there are so many examples of disadvantaged people who are never the beneficiaries of such efforts.
For example: numerous physical traits other than sex or skin color. Invisible minorities like eastern Europeans or middle eastern Christians. People who grew up in rural areas.
It's probably absurd to expect to define categories and provide special help to every group that could be defined. Instead, people should be judged as individuals, each of whom has faced a variety of obstacles and benefited from a variety of privileges, and whose potential can only be evaluated by considering the whole person, not a few checkboxes.