Welcome, and great first post!
If you read Phil's book, it's not really an unlikely pairing at all. They studied together and Phil was very much interested in the kind of avant garde art music that Reich has made a career of. Reich took composing to places it had never been and Phil certainly did the same thing with the electric bass, just to a broader audience.
Incidentally, out of all the avant garde composers I enjoy Steve Reich the most. His stuff is by far the most listenable and enjoyable to me - a few of his albums have been in my rotation for years, most notably a collaboration with Pat Metheny and an amazing album called Music for 18 Musicians:
I'd recommend it to anybody with an open mind, he has an amazing way of weaving textures together and letting things develop slowly, laying patterns on top of each others and finding the hidden music in the ways they intersect.
The most remarkable thing to me about this pairing to me is that Phil took an instrument whose traditional role is to play ostenatos and used it in a way that's almost completely melodic, and Reich creates music that uses only extremely sparse 2 or 3 note melodies stretched over many measures, whose real feature is an incredibly dense bed of weaving ostenatos!