I think the key issue here is that Attention is a temporal construct, meaning discovery is often tied to "being the first thing that comes to people's minds" which means SEO, reverse engineering the ranking algorithms, and constantly having to manage an "online persona". Note none of those things contribute to the actual work you're doing, just your "marketing department" (and whatever time/financial "budget" you intend to give it).

MrBeast figured out the YouTube algorithm - post early and often. Is that how we exist on modern Internet when every website/thumbnail is engineered by a team to maximize clickthrough rates? I agree RSS is useful, but it faces the same scalability issues if everyone starts filling up your RSS feeds. Given the limited amount of time you can devote to a particular task, we'll return to the era of A/B testing Headlines.

It’s still alive. Many sites still use it. Many people still subscribe to those sites. RSS reader apps are still being created to this day.