Except games aren't won and lost on ypg. In his 12 seasons he got "near" 400 ypg 7 of 12 times - 2009-2013 and 2016-17.
2009-2013 were pre-B1G West; the yards/play and scoring ranks in those seasons were bottom half of the conference in 2009, 2010 and 2013. 2011 had a 4th-ranked ypp and 5th-ranked scoring, while 2012 (prime Colter/Siemian/Mark) had bottom half ypp and was the only season where we scored >30ppg, which was also the only time we finished top-3 in conference under McCall.
2016-17 were the prime Thorson/Jackson years, and even then in 2016 we were bottom half in ypp and scoring, while 2017 had us 6th in ypp and 4th in scoring at 29ppg. Perhaps if Thorson doesn't blow his ACL in 2017, 2018 also reaches these heights as well, but that's not what happened.
Outside of those two years in the B1G West, McCall's other 4 offenses (2014-15, 2018-19) finished in the bottom 25% in ypp and scoring each year. I also doubt it's a coincidence that Fitz deciding to move away from the spread to a more "traditional" offense when the new divisions were created resulted in this offensive futility.