(Not entirely a fair comparison, should compare median<->median, not median<->mean. Also the grad student survey is from 2001, other numbers are more recent.)
As an example, UMN paid its football coach $1.2M in 2007. The university president earned $733,421 for 2008, placing him 7th in the nation among state universities. About $423K in salary, most of the rest was a retirement benefit.
Without getting into the issue of who "deserves" more, one might wonder at the discrepancy. Certainly it's nontrivial to find a leader of any sort, but it's not obvious why the market rate for football coaches should be higher. Football coaches compete in a much more limited market than university presidents--- can't the latter make the transition into the public sector and compete for CEO jobs? (Maybe not.)
1. University presidents don't have agents.
2. University presidents can't effectively tie their compensation to objective metrics, or to a particular income stream. They thus have a harder time convincing others of their "worth".
3. University presidents draw their salary from a pool of academic and administrative salaries--- often set by the Board of Regents or similar politically-influenced agency. Coaches negotiate with the athletic department instead. There is less public accountability and also less push for pay equity.