As a maintainer of the FeedIron plugin for Tiny Tiny RSS I see RSS as quite alive and kicking.

https://github.com/feediron/ttrss_plugin-feediron

On occasion I have needed to use a site parser like rss-bridge but honestly it's so rare that a site doesn't have rss (albeit often hidden from view). Just a hint for people searching for rss feeds the most common I find are:

/rss

/rss.xml

/feed

/feed.xml

/index.php/feed

/index?format=xml