I don't think that is an unfair point, though I'm not sure any of those situations are fair comparisons to this situation.
First and foremost, IU and Arizona are both better jobs than the one at Tennessee. Both programs are among the best in college basketball and have a far greater tradition than Tennessee. Additionally both programs are unquestionably the king of their athletic departments, unlike at UT where football and to a lesser extent women's basketball run the roost.
I think Thad Matta leaving XU for OSU is probably the best comparison, though I don't think Xavier was nearly as good of a program then as it is now.
Maybe I'm totally out of touch with reality but I just don't view UT as a plum job.
Xavier has become a really good program, they've got nice facilities and they've gotten to the point where they can compete for high level recruits with schools from the traditional power conferences. I just don't see the need for Mack to consider jumping ship any time a job comes open at a BCS school.