Let's be honest- Michigan under Bo in the 70s and 80s had some dominant runs where he was losing 1-2 games a year max- some years even going undefeated when you factor in ties- but it started to tail off in the late 80s and early 90s. Gary Moeller was losing 3-4 games a year, and if he was winning 11 or 12 every year, he probably wouldn't have been fired for his public drunken outburst.
...
Only way they'll ever come back is if they get a coach that can go anywhere in the country and load up with elite players. Like Urban Meyer can. Like Nick Saban can. RichRod couldn't. Hoke couldn't. Harbaugh can't.
That part of the Bo era is interesting because it woulda been a dang thing if it happened nowadays.
Year 1 Surprise upset to ruin things for OSU
Year 2 Undefeated until visiting OSU, lose (not too much harm)
Year 3 Undefeated all the way to the Rose Bowl, miss a chance to at worst end up at No. 2 because of a 1-point upset to 8-3 Stanford (who lost to SJ State)
Year 4 Undefeated to OSU, then lose to OSU by 3 at the end of the season
Year 5 Undefeated to OSU, tie No. 1 OSU to miss the Rose Bowl
Year 6 Undefeated to OSU, then lose to OSU by 2 to miss the Rose Bowl
Year 7
Undefeated to OSU with ties to six loss Baylor, four-loss Stanford, lose to No. 1 OSU then lost the bowl
Year 8 Start 8-0, lose at 5-6 Purdue, beat OSU, lose bowl
Year 9 Start 6-0, lose to unranked Minnesota at No. 1 team, beat OSU and
miss a chance to claim a national title with a low-scoring bowl loss.
Year 10 Have the decency to lose to a good (three loss) MSU team after only 4-0. Win out until the bowl game, where they lose again.
Year 11 Lose four games, three to close the season
I feel like modern fans would take issue with parts of this path.
As for getting elite players from anywhere, the issue is the same. Folks can go to place where its easier, so why wouldn't they?