Those student run radio stations that are working hard to provide a service that attracts listeners are a different story. I have seen/heard both, and the ones that are succeeding are definitely worthy.
Unfortunately, that's not necessarily the case. There are several examples of college radio stations that had passionate and devoted followings off-campus, but little to no on-campus audience. That makes it exceedingly difficult for the station to justify receiving college support; especially when it comes to "student activity fees" (or whatever the college happens to call it). It's hard to spend the inherently high costs (relative to other student activities) and justify the substantial financial risk of an FCC license when it's only benefiting the few dozen students who actually volunteer at the station.
That's true almost completely regardless of how big the off-campus audience is...UNLESS the station manages to tap that audience for fundraising dollars and leverage it for underwriting revenue. If the station can do that enough that it becomes revenue-neutral (or close to it) then it certainly goes a long way to making the parent institution less likely to arbitrarily dump the license. But such stations are relatively rare, and often it's very hard for them to accomplish revenue-neutrality unless they're in a fairly large market.
One thing I have found that's interesting is that I think new college stations, rare as they are, actually have an advantage here. There's a lot of tradition (or if you prefer: "hidebound thinking") at many college stations that make it very difficult for them to adapt to the new reality of how little relevance radio, as a medium, has in most 18-22yr olds' lives. Whereas newer stations are freer to adapt and really target the needs of their student populace and maximize the student activity aspect of things. In other words, that lack of relevance can more easily be leveraged as a "blank slate" to build on.