Even in those stone age pre-Internet days, the news that Elvis had left the building flashed around the world in a matter of minutes. If you thought Michael Jackson's death was a big deal, either you weren't around in 1977, or you were hiding under your pet rock. Had the Internet existed on August 16, 1977, it would not have slowed down--it would have blown up like a balloon, fallen off the toilet, crawled a few feet and died. Okay, bad metaphor...but you get the point.
Still, for you younger people, the MJ comparison is probably the best one, not only for the magnitude of the news event and the controversy surrounding the manner of death, but also for the grand opportunity we all had to really examine the consequence of fame and riches. Both men lived in such an insular world, cut off from the rest of humanity, surrounded by enablers, that their disintegration and deaths made it easy for us all to feel better about our own lack of fame and riches.
Here's a more direct, point-by-point comparison:
Rest in peace, Elvis. You'll always be The King. Excepting, of course, those movies where you're a race car driver.