So you think Apple should host podcasts for free out of the goodness of their heart? Apple's a business, not a charity/non-profit.
Podcast hosting for $20/year is a huge bargain. Libsyn's cheapest plan is $5/month with limits on storage. Add in the fact that you're published by one of the largest podcast directories on earth and the value is immense.
I personally don't have any trouble with them charging for hosting. I don't even have a problem with them offering paid subscriptions. I have a problem with them restricting consumption to their own Apple Podcasts app, because that makes the results not a podcast at all. Like Spotify, they're creating on-demand audio shows that require their client to listen to.
