Georgia Tech student here. One thing I would like to point out is that although the education given by Georgia Tech is excellent, I think that the real reason graduates make so much money is because of the Coop/internship program and the international studies program. It was why I chose to come here in the first place. I don't know the exact statistic but I believe more than 50% of students in Georgia Tech do a coop. In my major (Industrial Engineering), 70% of students do some sort of study abroad or work abroad.
Students that do coops usually get hired by the companies they coop for and they are usually hired at a position higher than entry level. This I believe explains the higher starting salary.