Podcasts are a very special case. They are self-contained content and have not much demand for anything around them. Any ad can be delivered inside the podcast or between streaming them. Videos are similar. Just look at Spotify, YouTube, Twitch, how many ads do they have outside the audio & video-streams?

And podcasts are even more special, because their main purpose is to be consumed without any interface, often even without any internet-connection. So the whole setup is already against classical advertisement.