Podcasting's resistance to takeover is going to be hard to replicate.
Podcasts are just mp3 files in an rss feed. Super established technology that anyone can publish. MP3 patents have expired and were basically unenforceable before that. RSS is completely open. Other ecosystems that have grown up in the social media era have higher barriers to entry and network effects to overcome.
Apple Podcasts is the behemoth of podcasting. All the other podcast clients combined don't come close to Apple's player marketshare. Spotify certainly has a lot of users, but not all of them listen to podcasts. Most shows have been unwilling to dump their biggest audience by going to spotify exclusive, so the shows remain just rss+mp3.
Apple also manages the only index of podcasts of any great significance and so far has been content to be extremely hand-off with it. They are happy to let anyone register a podcast in the itunes index and have only removed a few items for objectionable content.
With Apple as a largely absentee landlord of the podcast space and the extremly basic nature of the underlying technology shows have developed many different monetization techniques. Selling user behaviour/tracking is far, far harder in the podcast space since Apple doesn't share and controls the biggest client. Shows have turned to largely untargeted* ads, patreon, touring, merchandise, and various combination thereof. For many creators Spotify forcing them to use a specific form of monetization as part of being exclusive isn't as attractive as owning their own destiny.
*podcast hosting networks can get a source IP so you'll sometimes get a broad location targeted ad inserted dynamically into the mp3 as you download it, but the level of tracking is orders of magnatude lower than what's possible in a browser. For example, shows have almost no ability to know if you actually listened to a episode, just that you downloaded it.
So far Apple has been happy to largely leave the podcast world alone. They recently added some monetization options for show creators, but that's above and beyond their hand-off management of the biggest player and index.
Apple is a far, far bigger threat to the podcast world than Spotify ever was. The ecosystem as it currently exists depends on Apple continuing to the mainly nothing they have been. If Apple gets tempted to start selling even aggregate user behaviour from apple podcasts there will be very little to stop them.