I haven't had a chance to listen to this yet but I expect it goes into all the known reasons why the 70's Quad era died off along with possible ways(e.g., the Suzanne Ciani decoder approach) to bring it back.
https://www.digitalmusicnews.com/2018/11/01/quadraphonic-sound-podcast/
https://www.digitalmusicnews.com/2018/11/01/quadraphonic-sound-podcast/