Part of this was making the rounds on Facebook yesterday. The difference, of course, is that most Republicans in 1964 actually didn't want Barry Goldwater to be their party's nominee in 1964 (a Gallup poll on the eve of the convention showed Republicans wanted their nominee to be then Pennsylvania Governor William Scranton by a 2-1 margin over Goldwater) whereas a majority of Republicans now seem to want Trump to be their party's nominee.
Also, while the primary process was nowhere near as important in 1964 as it is now for determining the nominee, had it not been for Nelson Rockefeller's recent divorce, and probably just as badly for him, that he tried to cover it up, Rockefeller likely would have been the Republican nominee in 1964.