I just saw this and you're basically correct.
It has changed a tad in recent years, maybe due to the "we never get a break from it" but a refresher:
1968 - Nixon vs LBJ (we now know that was never going to happen - but Humphrey came up through McCarthy and RFK. And btw - in 1967, it was George Romney until his brainwashing remark)
1972 - Nixon vs Muskie (he won the NH primary but by "only" 9 points and that was all she wrote
1976 - Jimmy Carter didn't even register in the 1974 straw polls, starting his move in February 1975
1980 - Carter vs Reagan (YES, it happened this time)
1984 - Reagan vs Ted Kennedy or Walter Mondale (1/2 credit)
1988 - Probably But Not Sure Bush vs Gary Hart
1992 - Bush vs Cuomo/Bradley/Gore/Gephardt/Rockefeller
1996 - Clinton vs Dole
2000 - Gore vs Bush (caveat: the GOP in 1998 decided the poll numbers were enough for W)
2004 - Bush vs Mr SCREAM (Dean)
2008 - Hillary vs Rudi
2012 - Obama vs Romney/Huckabee (I'll grant this one since Romney was the more serious candidate)
2016 - Hillary vs Paul Ryan/Marco Rubio/Ted Cruz
2020 - Trump vs Bernie or Warren
I would add - and it was different back when state delegations chose the nominees - that in 1964, it was supposed to be JFK and Rockefeller. Tragedy removed the President and the birth of his baby with his new wife two days before the California primary finished off Rockefeller.
It would shake out even more bizarre this time if Biden isn’t running simply because the Dems are shuffling the calendar and moving Iowa out of the starter spot.
And despite another myth that endures, RFK wasn’t going to beat Nixon in 68 because he wasn’t even going to win the nomination, which wasn’t chosen by primary votes that year (for the most part) but by state delegations.
When Carter ran in 1976, the Ford campaign noted that it is a common phenomenon where a dazzling new candidate bursts on the scene, wins a bit - and their popularity craters when people find out their positions on issues or what dog they kicked in college. It happened with MacArthur, McGovern, Carter, Hart, Perot, Howard Dean, Bernie. It’ll happen to DeSantis, whose chief asset right now is “he’s not Trump.”
It would have happened to Colin Powell, too, and he knew it. So when he passed it was “we missed out because he could have been President.” Had he run, the moment he said he was for or against X, his numbers would have begun to drop.
That’s not to say DeSantis won’t win or even be the next President. But it’s a long way from where he is to where he hopes to go.