It’s always a good idea to address reality, but using numbers which have no basis in objective data is counterproductive. To what JHU report are you referring, and when was it issued? JHU currently has a lot of information for pre-meds(e.g. https://studentaffairs.jhu.edu/preprofadvising/wp-content/uploads/sites/33/2018/07/Guide-One.Fall-2018-2019.final_.pdf) but didn’t see anything claiming an 80% wash-out rate for freshmen.
And other than anecdotal information, there are no reports on the numbers because nobody can agree on a definition of “pre-med”. One only has to review the claims made by individual schools(some of which claim medical school acceptance rates of 75-90%) to see how easily the term “pre-med” can be manipulated.