Getting your photos off of Instagram is easy, according to the top 10 search results for "Instagram photo downloader". But even then, the distinction that you're not paying Instagram for hosting is notable.

> wouldn't hosts have the original source material that they uploaded

As far as I'm aware, Apple never resurfaces the audio after it's uploaded, even in your dashboard. Even if they did, making someone manually download and reupload every asset for potentially hundreds of episodes is sadistic. Moreover, you physically can't leave, because your listeners won't follow you to your new hosting service.

> These users aren't there just for generic hosting, but also for the network effects.

The network effects are limited to an app with only 40% of the market. Outside the US, that number is even smaller.

> just that there is fairly old precedent

Every podcast hosting service ever has allowed you to leave their service.

The bigger thing though is less about the data and more about your listeners. If you move to another podcast host, it's obviously important that your existing listeners move with you, and every public podcast host I'm aware of will happily redirect your feeds (as mentioned in the article)

With Apple you have to ask people to move, and asking people to take an action is necessarily going to involve a lot of churn and confusion.