I assume when you mention world class universities you're referring to UM Ann Arbor -- maybe Kettering too. Is there a lot of cross fertilization between the city and the schools? Do a lot of UM students live or move to Detroit?
This graphic from Forbes is pretty telling: http://goo.gl/4uBr
Even 8 years go it was bad. I worked downtown and could regularly hear gunshots from my office during the day.
If graduates do stay in Michigan, it's to continue working or studying in the Ann Arbor area. Only a handful do find jobs in the metro Detroit area (mainly engineers and consultants), but that's a trickle opposed to the flood.
Detroit's premier college is Wayne State University, and I can not speak for its graduates.