[skoocda]

Part of this issue is that most podcasts were designed to be free from the beginning, whereas music was always paid.

As a user, it makes sense to pay Spotify for music access, because Spotify, in turn, pays out a few fractions of a cent to the artist. But it doesn't really make sense to use Spotify premium for podcasts, when you can just download them directly or use various free RSS-based clients.

So why do so many people still consume podcasts on Spotify? 1. Because they're already on Spotify, so it's convenient, but more importantly... 2. Because Spotify realized they make more money if most of their users are paying, yet still consuming free (podcast) content. They don't pay out on podcasts per-stream like they do for a typical song. So ultimately, a premium user who consumes 100% podcast material is more profitable than a user who consumes 100% label-published music.

It's not a coincidence that Spotify has gradually taken over its homepage with podcast promotions, and promoted your "podcast library" as a first-class citizen, even placing it above your music library. It's all about profit margins, baby!