I find this kind of analysis highly problematic on two counts.
1. Reducing education to salaries.
2. Averages mean nothing without considering the standard deviations and distribution. Also this is not considering location and area of employment.
My take is if you are an elite student who can take advantage of what the university offers beyond just doing your class work an elite university makes a difference. For example, research, cross-disciplinary work. If not any good university will teach you the class curriculum.
