Cleveland is just a pro sports town. Nothing wrong with that really. Like Boston and Pittsburgh. Need top 5 teams or Doug Flutie for the masses to pay attention. And, OSU dominates up there as well.
I think the love of O$U comes in large part thanks to the ineptitude of the pro teams. The thirst for a winner is strong, and gathering around ever Saturday to watch the Buckeyes annihilate Minnesota or Indiana or whatever is cathartic for a lot of people here. I think "at least Ohio State won" is the official Monday morning consolation of Cleveland sports.
As for Cleveland State, it suffers the same problem all mid-majors do: They're not seen as "big time" by students, alumni or locals. Playing in a conference with IUPUI, Oakland (not California), etc. is the same problem as playing in a conference with a bunch of directional schools.
Last and certainly not least, CSU is a young university that until quite recently was mostly a commuter school with a lot of non-traditional students. They're working to change that and making great progress (often at the expense of Akron) but there's a long way to go.