Bob Dylan wasn't a big star early on; it was the release of his Greatest Hits album in 1967, and the mainstream success of the stoner anthem "Rainy Day Women #12 & 35" ("Everybody must get stoned!"), that really put him on the mainstream map.
I think that the celebrity is a really important thing, because we have the voice that's recognizable, that can educate people to make a difference and empower them to make a difference, and to also get things in motion with the people in charge that can effect change.