I am an RSS noob.. so maybe some of the above IS possible with RSS but consider the case of Medium.
Medium thought to incentivize content creators with cross-pollination of readers. Person A is an author and writes on medium because medium will promote content to its network of readers which is larger than the auidence that Person A has today. Person A inevitably also brings an audience with them albiet likely humble.
Medium MAY have failed for a few different reasons but I suspect retention being low for the larger majority of its visitors and also being unable to monetize in a meaningful way - I know this team is actively working on this and more and I am rooting for them!!
Substack is the new platform.. it focuses on the ease of capturing an audience and monetizing it. Today that is what most writers want for their efforts.
If you could somehow bake the ability to capture and monetize an audience into the RSS subs then perhaps we'd have something.. the reality is whatever RSS becomes it needs to provide a 10x better incentive to the content creator than the traditional means.. and if its just "another" channel.. likely it will be ignored for the more lucrative channels (ie build my own list.. or even sites like medium)
Its also worth mentioning Master Class .. but I dont know enough about them to make any real conjecture.. just that they seem to have cracked the nut on reputation and content creation. Who doesn't wanna learn how to shoot threes from Steph Curry?