Public recognition of what thing X they're using or relying on is not necessary for something to be "alive" or "dead", otherwise you'd have to say that TCP/IP is dead because I bet less than 10% of internet users know what that is and even less know how it works.
People using podcasts still rely on RSS. Spotify's and Apple's attempt to circumvent an open-standard doesn't seem to be working as podcastindex.org already has double the amount of podcasts registered.
E-commerce product feeds still (mostly) use RSS.
Everyone still uses RSS, they just don't know it.