Maybe, maybe not....
Here's another way to look at this situation. Harbaugh has a reputation as an excellent football coach, and he has had great success in three big time jobs - Stanford, San Fran, and Michigan. That's more than most head coaches can say, and it still counts for something despite his recent troubles at Michigan. In addition, Harbaugh is a better candidate than almost any typical NFL retread or unproven coordinator dude. So he's got two things heavily in his favor: (1) proven track record, and (2) weak competition.
Harbaugh's biggest challenge will be explaining the "collapse" at Michigan. First, "collapse" is an exaggeration. His record at Michigan, while clearly below Michigan Man expectations, is still 49-22, for a .690 winning percentage. Even though there isn't a whole lot of quality amongst those 49 wins, Harbaugh has undeniably taken Michigan up a level or two from his predecessors and made Michigan a solid top-20 program. The 2020 season can easily be explained away as an aberration due to COVID chaos.
And finally, Harbaugh's ace in the hole is the Michigan Man card: "I just couldn't succeed with that culture up there." We're always talking about the Michigan Man culture of arrogance and entitlement and living in the past. Harbaugh will play up that angle in job interviews (if he needs to do so) - he'll say that he tried to change the culture but it's just too ingrained in the program. Harbaugh's dumped on Michigan before, and there's no reason why he wouldn't do it again. Especially if there's an NFL job on the line.