RSS still contains full articles on a lot of personal sites. As you said, it’s about monetisation and control and when you’re writing with no plan to monetize there’s no point in not serving full content.

Yeah, and that’s my point. The problem is not technological, you can make a super readable HTML site by just putting text in <p> tags, and RSS readers for blogs that didn’t rug-pull their content still work fine. People lost interest in giving out something for nothing, so now the web is an ad-infested mess.

If someone makes a new tech that makes that impossible, 10 principled FSF-enjoyers will write content for it and nobody else. Web standard bloat is bad, but it didn’t cause this problem, and you can’t fix it by creating a new spec.