For decades, The Grateful Dead was a way of life for the subculture of fans who went to hundreds of shows and followed the Dead all around the country. The band allowed fans to record during their concerts, which spawned an ecosystem of bootlegs.
The popularity of the Dead's music still endures. There's even a 24/7 station on Sirius XM satellite radio, where fans can listen to bootleg concerts in their entirety and to tracks from their deep studio collection.
"It doesn't surprise me" that the music lives on, Weir said. "It wasn't written for the purpose of selling a million records or appealing to the current trends. ... We had no talent for that, so we abandoned that way early on."
Despite Garcia's passing, the music of The Grateful Dead continues to evolve. Weir is scheduled to play a show of Dead tunes Thursday night with guitarist Warren Haynes and the San Francisco Symphony.
Weir said with a smile that Garcia would have probably thought of it as "gilding the lily," but added he "isn't around to knock us in the head."
—By CNBC's Senior Economics Reporter Steve Liesman, who also plays in two bands; the Dead tribute group Stella Blue's Band and Steve Liesman and The Mooncussers. Follow him on Twitter