We have to start by talking about the Grateful Dead first, even though this article is about the 90's.
The Grateful Dead, as anyone in America or Europe knows, were the psychedelic granddaddies from the original Haight Ashbury. Faithfully followed from city to city by thousands of Deadheads, who contributed $500 million to Dead coffers over the years.
Depending on whom you asked, their shows were communal experiences between band and audience in which the group's semi-freeform playing would reach transcendant heights; their music was a living, evolving entity, energy waves even, lifting the listener to the outer fringes of space, and gently bringing them back to the earthy soil once again.
Or, their shows were out of tune and sloppy, their music lumpen and dull, their singing weak, their rhythm section limp.
Based on the evidence, the truth was somewhere in between. At their peak, from the late 60's through early 70's, they really were pretty great. As a live act, their peak extended well into the early 80's, until about the time Garcia started having serious health (and drug) issues. After that, it wasn't even a night-by-night question of off or on; the Grateful Dead became a band of great moments, like the second verse of Stella Blue on 11/23 or the transition from The Other One into Space, 6/14. I loved them myself, but after Garcia's coma in '86, the band seldom held it together for a whole set, let alone a show. And sadly, they just sounded worse every year. But they had their moments.
But it didn't matter to the Deadheads, faithful through three generations, oldtimers and young timers side by side at shows, although in the very last days, the oldtimers started disappearing. As the band deteriorated, they set higher and higher attendance revenue records; the Grateful Dead made more tour money than any other band in the 1990's, and they folded before the decade was half over.
Perhaps a reason for the box office records, one not everyone might care to admit, was really the parking lot scene at the shows. If you were going to find LSD or 'shrooms, or something else, the parking lot was the place to go; a lot of the dealers skipped the shows themselves. But many were there for the music, even then; to rekindle that spark once more, however cold it was becoming. Until, in the end, it was extinguished.