A number of factors contributed to Goldwater's defeat in 1964--Goldwater's reluctance to run, strife within his campaign team, the refusal of the Rockefeller wing of the party to actively support him, etc. The election was hardly a repudiation of conservatism.
Huh? Victories and defeats in politics aren't permanent. You can be crushed in one election and win the next by a landslide, but the 1964 election was about as crushing repudiation of Goldwater's conservatism as you could get.
Maybe there's something wrong with the concepts involved. McGovern was definitively repudiated in 1972. McGovernism won in 1974 and 1976. The GOP was repudiated in 2006 and 2008, but came back to win in 2010 and 2014.
Parties and ideologies survive electoral defeats, but you've got to acknowledge the defeats when they come along.