8:30 Jethro Tull 10:20 ELO 12:15 James Bond

allusions aren't derivative in a negative way

As you might have suspected, the Grateful Dead songs I've heard are folky knee slappers such as Uncle John's Band. That is what I think of when I say not complex. Like, fall asleep in the elevator not complex. Your example is so complex it has allusions to way more than the 3 styles I mentioned, while not having a cohesive thread throughout, which is much like the conversations I've had at hippie festivals :D So I stand corrected, I see the Dead can get complex.

try Snarky Puppy Elephant Revival TAUK King Canyon FORQ Lettuce Explosions in the Sky