Compared to the necessity of creators to have access to expensive physical infrastructure, not to mention publishing power structures needed to negotiate to get their product out on TV or radio – it's clear where the core strength and appeal of podcasting lies.
It's the last, but a pretty solid mass medium standing democratic in the way it's available to everyone, cheap to produce and consume, and discoverable with minimum effort and investment in terms of equipment and service fees.
If you have an internet connection and basic recording equipment, can cover bandwidth costs, and know how to use RSS as a content distribution tool – that is pretty much all you need to be podcasting “to everyone.”
Nevertheless, to be able to reach a wider audience, it's necessary to be discoverable in podcasting and/or streaming apps, that allow their users to search podcasts listed by dedicated directories.
Using a free and open source podcasting app will provide you with several “diverse” podcast directories to choose from: the overpowering and omnipresent one maintained by Apple, and then some David(s) to this Goliath, like open source gPodder and Fyyd.
Three choices, particularly with one obviously disproportionately dominant as far as “normal” users and podcasters are concerned, doesn't seem like much; but it's still better than just one, controlled by an entity beholden to nothing but itself like Apple, or others very similar to it like Google and Spotify.
So what's wrong with that? Don't Apple and its giant “co-conspirator tech brethren” already index everything published on the planet anyway? Well, the reliability and future viability of this model is now doubted and challenged by “podfather” Adam Curry and developer Dave Jones, who are throwing their weight behind a new open directory that's available to developers who wish to include it in their podcast apps.
It's called simply, “Podcast Index.” The goal is to provide an alternative to Apple's dominant index that Curry suspects is now being tinkered with – as opposed to the goal of Podcast Index to uphold some “podcast pioneer” standards of universal availability, for free, and for any use.
The main concern around Apple is that it's “a very centralized private entity (…) controlling pretty much what everybody considers the default yellow pages for podcasting” – while the solution is to offer an alternative as “an open project to preserve podcasting as a platform for free speech.”