[jeffwass]

The Dead are explicitly mentioned :

So while Phish undoubtedly has fewer fans than Madonna, the ticket revenue per fan is way higher because fans loyally attend multiple shows. Not since the Grateful Dead has a band built a following as loyal as Phish. And like the Grateful Dead, Phish merchandising is a big business as fans gobble up Phish t-shirts, baby-onesies, and hats.

[MontgomeryPy]

Yes saw that but no suggestion that perhaps consciously or subconsciously they followed the Dead's template since the article focuses on their business model

[freejazz]

The Dead's template started as going on tour, selling LSD until it ran out