https://www.rssboard.org/news/219/downloading-50000-podcast-...podcast-standard.org:
"The data presented on this website is derived from a collection of 155785 podcasts, with a total of 17648609 episodes, sourced from the iTunes and fyyd podcast directories."
Those are public resources. Anyone can access them for free.
To search:
https://podcast-standard.org/search/podcasts/?q=%s
The second "S" in RSS stands for simple. Why make a "simple" standard. Perhaps because it creates flexibility for everyone who wants to publish a podcast, everyone who wants to host a podcast, and everyone who wants to search and retrieve a podcast feed. NB. RSS is focused on feeds, which are nothing more than marked up text files. It does not address listening to a podcast. Listening requires an audio player. A podacst listener may choose any audio player they prefer. RSS feeds just provide a URL for the audio file. Listening is outside the scape of RSS.
Because RSS simplifies publishing, hosting, searching and retrieving feeds, there an endless options for how to do these things, e.g., how to search and retrieve a podcast feed. This means that way that one person searches and retrieves a podcast feed may differ from the way another persons does it. There are hundreds of computer languages that could be used to search and retrieve, dozens if not hundreds of existing programs that could be used, and countless different approaches to accomplish this relatively simple task.
Hence, the way that I search for a podcast feed may differ from the way someone else does it, and vice versa. One could use relatively tiny, simple programs written in minutes by potentially anyone, even a naive end-user like me, or one could relatively large, complex programs written by multi-billion dollar companies that provide advertising services or by their "non-profit" business partners, e.g., Mozilla. These programs are so large and complex almost no one outside of the companies wants to modify them, even when they dislike what the programs do. In case of any doubt, in the preceding sentence, "programs" means "modern" web browsers.
Thus a benefit of keeping a standard "simple" is that is allows for "There is more than one way to do it." Gigantic, complex programs and the involvement of multi-billion dollar companies is not a requirement. Ironically, Apple, a 350+ billion dollar corporation with a closed source web browser running on non-free operating systems, has probably the most complete directory for locating RSS feeds. Go figure.