Frank was fired because he wasn't going to keep us to what we were accustomed to. Bo gets to stay because we are accustomed to it now! So ask yourselves. If Bo had followed TO how would you feel about him now?
If the bold statement was true Frank would have been fired after the 2002 season. There was a lot more going on regarding Frank's firing than was made public. It wasn't as simple as wins and losses.
I think you have a good point in that Bo wouldn't have been as well-received (or, his "honeymoon" wouldn't have lasted as long) if he had succeeded Osborne rather than Callahan. The state of Nebraska Football was far different after Osborne left compared to Callahan, as we all know.
The "honeymoon period" has long since ended with Bo. He doesn't get the grace of "better than the last guy" anymore, and hasn't for over a year. The honeymoon was over for all but the unrealistic die-hards back towards the end of 2010.