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.