In absolute terms, it would really be much cheaper to provide the resources to push the gifted students than what is spent on the lowest-performing students. $1000 dollars worth of books, software and a cheap laptop per student per year is far cheaper than hiring a one-on-one ed tech at $20-30k to babysit children with severe learning disabilities and behavior issues, or the still greater sums on the "severe and profound" students that have to be "educated" until they age out.

Further, in terms of societal impact, the productivity from a well-educated gifted student is going to greatly outmatch the gains from 'educating' a low-achiever.

Regarding the "why" notion of so much effort being put into the kids at the bottom, it's my personal experience that the most vocal parents tend to come from the pool toward the bottom, be it physically or mentally disabled. They have a point, certainly, in asserting their children have a right to equal access...but I do think the costs associated with such access typically burden the state far more than the parent in terms of accommodation. As in, some special needs kids genuinely don't belong in mainstream education environments, but through parental outcry and pressure, sometimes this gets over-ruled.

What has bothered me the most, time and again, is the assumption that smart kids will 'turn out fine' without additional challenges and, by contrast, there's any reasonable ROI expectation with the a large portion of developmentally challenged / mentally deficient kids. It's a sensitive issue for sure. Somehow just postulating this kind of thinking draws up feelings of insensitivity, but I'm trying to focus on some empirical observations. Difficult tight rope!

They're required to make sure the kids at the bottom can pass. The kids at the top already are passing, so spending money on them is extra.