I think both Mondale and Ferraro knew that their campaign would not end in victory. Did they predict they'd lose almost every state, I doubt it but I think they knew it would be a pretty one-sided election.
After the conventions they knew it was all over but the vote counting.
But after the primaries Mondale had a double digit lead and the media was talking about President Mondale. A few months later the economic recovery had hit, everything went Reagan's way and the situation was completely reversed.
Mondale never was ahead of Reagan at all, much less double digits, in any Gallup polls in the entire year of 1984. Which poll had Mondale ahead by double digits after the primary?