Let's say you want to use only the endowment income from a $5M gift and wanted to provide 5-year awards. For the awards to be meaningful, perhaps you choose $5000 awards (that's roughly 20% of Virginia Tech's total cost of attendance) that are renewable each year up to 4 years total. That means you can award ~12 new scholarships each year. While those students would certainly be grateful, that doesn't move the needle very much in a College as large as engineering at Virginia Tech.

It gets even worse when you consider that increases in tuition decrease the real value of the award. As a result, you have to increase the amount, reducing the number of awards you can make. Furthermore, while you've helped the student, the institution is no better off financially than it was before. (It's not collecting more tuition money overall.)