From the originals (Monterey; Hendrix and Joplin) through hippies 2.0 (Lollapalooza; The Grateful Dead and Phish) to hippies 3G (Bonnaroo; Sound Tribe Sector 9 and, still, Phish), “what’s amazing … isn’t how much they’ve changed. It’s how much they haven’t, especially as society has changed around them.”