The use of race in elite college admissions was never about increasing the diversity of lived experiences, it was about being able to maintain a university filled with people from high-status backgrounds while outwardly appearing to be representative of the society they exist in.
It's trivial for them to get the diversity they want by prioritizing applicants from underrepresented school districts and giving a boost to applicants of lesser means, but this would result in them needing to make significant compromises in the prevalence of students from upper class backgrounds.
One of the justices alluded to just that in the majority opinion - colleges could clearly forego "legacy", major-donor and athletic admissions, but they seem to prefer non-rich asians, whites and indians to carry the downside of the agenda.
It's trivial for them to get the diversity they want by prioritizing applicants from underrepresented school districts and giving a boost to applicants of lesser means, but this would result in them needing to make significant compromises in the prevalence of students from upper class backgrounds.