The "Week-To-Week Grind" of Major Conferences: Is It Actually A Thing?

From my Utah profile at the mothership:

There is a series of typical, semi-patronizing 'worries' analysts usually come up with when discussing a historically mid-major program taking on a tougher slate of major conference teams. Are they athletic enough? Can they compete physically? How will they avoid wearing down? The answers for Utah heading into 2011: 1) Yes, 2) Yes, and 3) By being as fast and physical as everybody they play. In a USC-less Pac-12 South race, Utah is as big, fast and physically capable of anybody they will be taking on.

This segues right into a question from today's Stewart Mandel mailbag at SI (thanks for the link, Stew! And the Missouri plug!):

Given the historical argument from the AQ conferences that it's easy to get up for one game, but the non-AQ schools can't handle the week-to-week grind that the [insert major conference, though typically Big Ten or SEC, here] teams face, is it safe to say that Utah's Pac-12 record this season has the potential to do more for or hurt non-AQ schools than could the results of any bowl game?

So here's my question. If, in the seven examples I listed earlier today (Arizona, Arizona State, Cincinnati, Colorado, Louisville, Oklahoma State, Texas Tech), teams' average schedule-adjusted performance (Est. S&P+) actually increased by an average of 2.9%, does that prove that the idea of the "week-to-week grind that the [insert major conference, though typically Big Ten or SEC, here] teams face" is, more or less, bunk? Five of the seven teams above saw their win percentages decrease, but it seems to me that's due simply to playing more good teams, not some cumulative "grind."

Now, granted, of the seven teams listed, two moved to the Big 8 before it was a truly great conference and two moved to the Big East (which is a major conference but isn't the SEC, if you catch my drift). Nobody from this list moved to the Big Ten in its prime, and the only teams the SEC has added any time recently was Arkansas (which saw their wins decrease and Adj. S&P+ stay approximately the same in moving from major conference to MAJOR conference) and South Carolina (whose wins and Adj. S&P+ decreased slightly), but still ... this was an upgrade in competition, and most teams handled it without any signs of a "grind" issue, only the occasional "We weren't good enough to actually make this leap at this moment in time" issue (*cough* OSU *cough*). Utah has passed almost every test it can pass in the Mountain West (which is a better conference than any of the other seven left), and I do not expect any sort of "grind" effect ... especially not in the Pac-12 South with a schedule that avoids Oregon and Stanford.