And of those 30K who have stayed in Syracuse, I would wager that at least 25K grew up in the area and decided to attend SU. It's a very tough area for recent college grads to make a decent wage/career unless you have connections.
The city should put more focus on all of the kids that grew up in the area and go off to SUNY schools. Many of those kids would love to stay in the area near family and have a career but it's difficult in this area. It goes back to the fact that it's not a great market for recent college grads when you compare it to Atlanta, Charlotte, Raleigh, NYC, DC, Boston, etc.