Why isn't real media (.rm) used more often?

Well, after playing endlessly with AE and rendering with a gazillion type of codecs, I came to the conclusion that people overlook realmedia (rm files) too much ! I know that most people think that rm files are sluggish to download (who hasn’t had a 1/2hour of ‘buffering’ for his videos) but here’s a test render I did:

Gif: 130 kb

Quicktime mov files (sorenson 3, okay quality, not the best): 165 kb

and Realmedia rm file, encoded to a pretty good quality: a mere 31 kb !
http://www.mlkdesign.online.fr/files/kirupa/m_rm.rm

So I’m beginning to wonder why people post (for example movie screeners) in a .mov format…