Can we stop being 'Presumptive'?

Yes, I know saying so-and-so is the "presumptive" nominee or candidate is correct, but why can't we just use the more common term "likely"?
A quick informal questioning (highly unscientific) of some students and adults in various organizations to which I belong showed that a significant amount of time, when asked what presumptive meant to them, they confused it with presumptuous. In other words, the word, correct or not, has tonal and usage problems that "likely" does not. (So much so that the authors of "Working with Words" point it out as a problem in their usage section.)