It can be even argued that McGovern slightly over performed on election day, especially popular vote wise. I think in some polls Nixon was beating McGovern by nearly 30 points. In comparison, Mondale underperformed on election day. Reagan was consistently well ahead, but usually by 10-15 points with some polls having it around an 18 point lead, which was right on the money. I remember the pundits saying that Reagan did a little better than expected on election day, especially coming so close to a 50 state sweep.
To the underperformance point: Was Mondale expected to win any states besides Minnesota? I’m sure pundits may have thought Massachusetts was going to McGovern?-