The telepathic spirit of jamming
John Mayer and Phil Lesh have opposite sensibilities, and that accounts for the biggest difference between Dead & Co. and the Grateful Dead. In the original Dead, it was less about the band keeping a backing track while people took turns with over-the-top heroic solos; instead, they were all soloing at the same time. At their best, there was no focal soloist; they were all listening to each other discerningly, warping forward in an unpredictable direction. They were not trying to compose a solo, but predicting where their bandmate would be in 5 seconds, and trying to augment that. The original spirit was more “telepathic” and unpredictable, where the worst of Dead & Co. feels like a literal circle jerk (John's orgasm face is not the problem; the problem is they should all have that face).