The problem is not with teens like her. She is exactly the type of kid who every “elite” college wants to have. There are tens to thousands of kids with the resources that she had, and only a handful do as much as she did.
The problem is identifying kids of her abilities in populations with fewer resources. In theory, it should be fairly simple - you see what they do with the resources that they have. Unfortunately, most people from wealthy populations have difficulty in doing so, since the rarely have any idea of the resources that are available to kids who grow up in poor families. AOs at “elite” colleges, are, invariably, not from poor, or even lower middle class families, so they have difficulty extrapolating.
So kids with 1/10 of the resources that this extraordinary young woman had are still expected to do at least half as much as her to be considered in the same category as her.
I will repeat something I’ve written before. The problem is not the the kids who are accepted are not, in general, really qualified. The problem is that the indicators that are used to identify the qualifications are calibrated to the very wealthy or to those with a lot of resources.
By having 70% from the top 20%, most “elite” colleges are missing the majority of the top applicants.
The problem, IMO, however, is less the private colleges, but public ones, like UNC (60% from the top 20%, 27% from the top 5%), UVA (67% in the top 20%, 32% from the top 5%), Michigan (66% in top 20%, 33% in the top 5%), and the worst public offender, W&M (72% from top 20%, 35% from the top 5%). If they want the most academically talented kids in their state, they should be doing a much better job finding those who are not in the top quintile by income (and making their education affordable).