I think both candidates thought it would have been over on Super Tuesday, at least initially.
Yes, that's true. It wasn't that Clinton arrogantly thought that Obama would be finished on Super Tuesday. It was that Clinton (like most other people) thought it would basically be over one way or the other on Super Tuesday. That it would be too difficult for the loser of Super Tuesday to ever stage a comeback, and that no plans would be able to save them. It's not as if everyone knew in advance that the two candidates would finish within about 1 or 2% of each other on Super Tuesday, making it virtually a tie.
Still, even if it was unlikely for the race to go on this long, they should have had contingency plans just in case. However, I can understand why planning campaigns in 22 Super Tuesday states might have offered too much of a distraction to worry about what comes afer.