In the speech, Carter spoke of "this crisis in the growing doubt about the meaning of our own lives and in the loss of a unity of purpose for our nation," which apparently suggested malaise to a lot of people.
A year and a half later Ronald Reagan was president. The moral of the story would appear to be: don't ever get all philosophical with the American people, and for god's sake don't try to tell them the truth about themselves. That's never a good idea.
Better to tell them what they want to hear instead of what they need to hear, if your goal is to win elections.
(Cross-posted at Lippmann's Ghost.)