Valid points, all. One way around itis to have SU open up ALL events (sports, music, theater, art shows, everything!) to the seniors in an attractive manner (lower prices, better seating, access to facilities, volunteering options, get-togethers, etc.) and have developers build communities advocating, perhaps including these activities as amenities, as enticement to buy. The communities need not be limited to 55+ or may include sections that are 55+. SU also has to be more open to the community; how, I don't know, I no longer live in the area.
My good friends in College Station own a house not on university property, but close enough to actively involved in what they want, having seasons tickets to football, baseball, theater, purchasing packages for hoops, softball, and other things. They are volunteers at the Pres. George H.W. Bush Presidential Library, have access to some university facilities and groups, etc. The whole package. College Station caters a bit to the retirement crowd, which is closely related to/associated with the alumni crowd. The city encourages cross involvement. I know, Syracuse has a bit of a ways to go on that account and SU has a bit of a way to go involving the City of Syracuse with the University.
I get the territorial nature of the self-interest fights, yet working together, they really can build and rebuild a lot in Syracuse. When the City works with education and industry, it is amazing what can be accomplished. They all need each other and should behave more like adults than in pure self interest. It takes work but the benefits are even grater than pure self interest of the City, SU, and industry.