The judges are out as to whether Kerry 'swept' all three debates. I've even heard a left-wing source say he won 1 handily, tied 1, and slightly won the other.
But even if that's the case--are you voting for somebody based on 3 hours of them speaking, or on the 20 years of his job history? Personally, the debates have never been a deciding factor for me. Talk is cheap.
And obviously Kerry was not 'considered better on almost every issue' by half the population. Even if he was, you say 'except morality', which to some people, is still an important issue.