Don't you think that if browsers rehabilitate a native "RSS one click subscribe" feature, with better UX (RSS actions/reader nicely integrated to the browser) it could revolutionize the way we subscribe to content updates, removing the need to rely on emails/newsletters in a lot of cases (then being more eco-friendly)? Users would receive content updates notifications directly in the browser, their feeds being synchronized through their browser account, etc. Web developpers would just have to place subscription buttons: <input type="subscribe"> And a W3C Standard would unify how browsers should implement the "Subscription" feature, focusing on UX (I feel this is the point influencing usage data for the most part, RSS still being a tech-savvy thing). Feeds handling [https://support.mozilla.org/en-US/kb/feed-reader-replacements-firefox was removed in 2018] in Firefox.