The former Dean of Georgia Tech's CS dept quotes John Hurt from the NSF as claiming: "Of 3,200 universities, perhaps six have made significant amounts of money from their intellectual property rights." I don't think there have been any blockbuster university (non-bio) tech patents since the Akamai (MIT) / PageRank (Stanford) pair ten years ago.
Prime case is the Mosaic browser IP and the University of Illinois Urbana-Champaign. All the research was done by the National Center for Supercomputing Applications for the university, and when it was completed and released, didn't really bother to try to get anything from it. The university basically sold the rights to an offshoot company for a very small fee-I believe it was under $1 million, and didn't see any money from it after that.
I'm not sure which version of the calculus is right, but it's at least plausible to me that universities stand to lose more in donations/prestige than they'd gain in royalties if they took stricter approaches to patent licensing.