> But RSS isn’t the reason why podcasts are popular

I don't understand the relevance of this point. RSS is infrastructure so why would end users need to know about it? They don't know about IP addresses when they type a domain name into a browser, but you wouldn't argue that it isn't mainstream tech.

> Some of the most popular podcast platforms like YouTube and Spotify are completely detached from RSS.

This is a quibble and beside the point, but neither of these platforms have podcasts. I can't subscribe to their audio tracks in a podcast player.

But again, I don't see the releavnce. Some platforms not using RSS doesn't detract from the usage that RSS does have.

> Decentralizing that type of interactivity has only recently been achieved by ActivityPub.

This was not a recent occurence. ActivityPub is descended from a long line of work (Ostatus, pump.io, etc) some of which used Atom. Dave Winer (one of the developers of RSS) is experimenting with building a full social network on top of RSS. Podcasting 2.0 (https://podcasting2.org) is working on adding chat/commenting to podcasts. Your original assertion was that RSS can't be used to build something like TikTok, but there have been multiple projects built with either RSS or a close enough analog that show it can be done