Having been involved in podcasting for almost a decade now, I take a generally pessimistic view of the future the RSS based distribution system of podcasts. It largely only exists because of decisions made by Apple many many years ago that they have not gone back on. They set their APIs to public which allows a podcaster to submit to Apple and then all of the various podcast distribution platforms can pull in that data to allow you to subscribe to the RSS on their platform. Apple's introduction of Podcast Subscriptions was their first move away from this model (with Apple hosting the audio) and I wouldn't be surprised if they moved to get more control in the future.

When Spotify entered the market they paid a lot of money for exclusive content, but for the 99% of podcasters their interaction with the space was the same as Apple, submit your RSS and it serves it from your hosting. However, Spotify also bought two podcast hosting platforms: Anchor and Megaphone which ends up blurring that line a bit. As far as I know the Anchor/Megaphone hosted podcasts are not treated differently by Spotify, but that could change at any time.

The recent change from Google with the retiring of Google Podcasts in favor of Youtube Music is a tremendous step in the opposite direction. Youtube Music does NOT use the RSS based distribution method, with podcasters uploading their files directly to Youtube. Google even offers an RSS import.

From all of the metrics I have seen the above three platforms make up 80%+ or so of the podcast user base. So if they made changes to make things less open podcast creators would be forced to follow. Making it feel like the openness of podcasts is, at least in 2023, more of an illusion or an act of charity than anything else.