There are tiers of schools when it comes to college football:
Tier 1 - Traditional Powers - Notre Dame, Michigan, Alabama, Texas, Nebraska and not many more besides these. These are the best jobs in football because of the prestige, pay and exposure.
Tier 2 - Football Factories - Oklahoma, LSU, Florida, FSU, Georgia, etc. These are the kind of jobs that pay well but don't have the same prestige as Tier 1 schools. This is why Bob Stoops, Mark Richt, etc. were talked about in the ND coaching search.
Tier 3 - Reasonable Expectations - Iowa, Stanford, Oregon, etc. These are the schools that have never been perennial powers so the alumni are totally content with making bowl games and going 8-4. Definitely the cushiest jobs in college football where you can still compete for a NC... but they don't pay nearly as well as Tier 1/2 schools and don't have close to the same prestige.
Tier 4 - Also-rans - Northwestern, Arizona, Baylor, TCU, Utah, etc. These are schools that might compete under a certain coach but are doomed to mediocrity in the long run. Coaches use them as stepping stones or as a lifelong destination depending on their persona. Every single coach at also-ran dreams of coaching at a Tier 1/2 school OR retiring at their also-ran.
Tier 5 - Crappy schools - we all know who they are... and they are simply rungs on the ladder to better positions.
Hopefully you agree with me on these tiers. To argue that Stanford is not a Tier 3 school or that Michigan is not a Tier 1 school is to be ignorant of history. People like Harbaugh played/lived through when Michigan was a perennial power and Stanford was a perennial laughing stock. Heck, as soon as 4 years ago that was the case before Rich Rod drove UM into the ground and Harbaugh built up Stanford.
My contention is that any coach - unless they seriously think they have no chance to win immediately at the higher tier school and are auditioning for the pros... which I admit could be the case with Harbaugh - will upgrade tiers if given a reasonable opportunity/conditions to do so. That is why Lane Kiffin never blinked an eye going to USC nor did Rich Rod blink an eye going to UM nor did Brian Kelly blink an eye going from CM to Cinci to ND. Coaches (mostly) aim to use the lower tiers as rungs on the coaching ladder. And Stanford is nothing more than a middle rung.