To be fair to your theory, Reagan was a beast of charisma, wasn't he? I don't think JFK could have beaten him. Mondale was the party faithful rewarding their own in spite of the coming carnage (see also, Dole).
Indeed, that explains to me the one case I'd argue against in your version of recent history. Bush '88 seems in retrospect to have been less charismatic than Dukakis. Or they were very, very close in their wonkiness. But Bush senior was given the benefit of the doubt by the electorate. He became more charismatic in being associated with the Reagan force of nature even as he was actually a big ole stiff. That eventually came out by 1992.
I'd argue the same osmosis almost carried Gore to the presidency. A few moans here and a blue dress there made it much closer than it ever should have been. Problem is, Gore never figured out how to embrace the Clinton legacy (and in so doing would have become more charismatic) while distancing himself from the more distasteful behavior. Still, Gore looked to me, at the time, like a one-term president because of his lack of charisma.