What's the context of those stats? Meaning how do other coaches compare, even if I trust your memory of the numbers.
Considering the bottom half of your own conference is guaranteed to have at least 4 losses, probably five and likely 6+, plus usually three non-conference opponents who aren't great, I'd say it's would have to be pretty extraordinary to NOT beat a bunch of teams that fit that description each year.
Pure statistics would tell you that six teams on your schedule each year will have 6+ losses. So having 6-7 teams with 6+ losses and probably 7-8 teams with 5+ losses is a pretty typical year.
So I would agree with your point that those numbers are probably pretty common. Bo definitely did have much for big wins. But he didn't have much for "bad" losses either - "bad" in this context being teams with losing records. Kind of the story of the on-field results overall - good but not good enough.
Fair assumption to make but in reality the shoe just doesn't fit in this case. Especially as one looks at Bo's first few years as Nebraska HC 2008-2010 as member of the Big 12 North. In those three years CU, KSU, ISU, KU were not just bad, they were awful. Will throw Baylor in that group since we're crossover opponent from south for 08-09. These 5 schools completed 14 full seasons in those three years, with best year for any of them being I believe KU in 2008, I think they went 8-4. Of the others, there was I think one other winning season, the average record was 4-8. That is dumpster fire bad. Worst division in history over 3 years, of major conference in D1 football bad.
Count those 5 teams plus 2-3 weaklings in OOC and just about any coach falls into 8 or 9 wins. No bad losses? ISU 2009, WI 2012 Big 10 title game to 5 loss team, WI 400 yards rushing.