That would only be bad if Apple had a monopoly or the other platforms all copy Apple and it cannibalizes the freedom of podcasting in general. But if it’s limited to a few ‘premium’ shows/platforms - while 99% of other content is open - I don’t really see it as a problem.
Particularly if the only way they can finance the shows is by limiting it to their platform, then I’d rather have them still produce that content than not at all…
Sometimes it’s the only way it makes sense as a business, there is no open alternative.
Spotify, Netflix, and every other streaming service functions this way with non-portable content and providing clients on every platform. While piracy fills the void for those who can’t pay or access the platform (for geographic reasons or w/e).
But I have to agree with the OP, it isn’t really a podcast anymore if it’s tied to one platform. It’s more like an on-demand XM radio show than a podcast.