I enjoyed this. A lot of it is speculative, as the author herself admits. Really, how could it be anything else - how precisely would one go about proving, for example, group dancing helped to build social cohesion among Neolithic hunters? But I'm okay with the speculation.
One reason I'm okay with it is that Ehrenreich doesn't make over inflated claims about what she's doing. She's entertaining some theories and raising some questions based on her reading on the subject. She's not pretending to have the last word. Which seems fair enough to me.
Also I'm okay with it because the questions and speculations are kind of fascinating. Was life different for people when public dancing and celebrations were a regular and frequent part of their lives? What were the social and emotional functions those celebrations played? Why have they declined where they have declined, and how has that changed people's experience?
Interesting things to think about. Interesting historical tidbits, strange parallels and commonalities, all of which to me at least are great loads of fun. Regardless of whether the questions are entirely answerable.