Thanks Andrew. Great perspective and topic.
It seems to me that in the oil analogy, Joe himself is the oil, and the pipelines to his customers has been the Apple Podcast app, Google Podcast app, Youtube, and a dozen other podcast apps. His content flow has always been subject to those apps' terms of service and executives' whims, so he isn't losing his relationship with his customers, he is switching pipelines.
On his shows he laments censorship, feeling frustrated with pushback from the "pipelines" on which guests he can have, what content he can cover and whether he can air short audio/video clips without getting copyright strikes against him.
I agree, his exclusive "pipeline" deal will diminish his audience, as it's uncertain what percent of customers will follow him to Spotify, but assurances from Spotify regarding creative control will mean his product will be unfiltered, authentic and have a guaranteed flow. This is creative enhancement and guarantee of delivery, which has value.
Joe is leaving the ad-revenue business, which is subject to whims of Google and Apple, and is getting into the pipeline business, exchanging a diminished audience for creative control, guaranteed delivery and more money. To me, it's a win.