If you weren't in front of the family Magnavox on that night in September of 1956 when Elvis appeared on Ed Sullivan, and changed American music--and maybe the world--forever, you can't imagine how large he came to loom in American popular culture. Granted, it was a different kind of big than we have nowadays. Not a bigger big, just a different kind. There are probably a dozen or more people walking around today who are more famous than Elvis ever was. Heck, a portly guy in highwater sansabelts and white socks got a gazillion hits worldwide on YouTube for a song no one understood about a place and lifestyle very few outside of Korea had ever heard of.
I guess what I'm trying to say here is that there is a difference, culturally speaking, between "big" and "massive."