All who started on the journey are considered Eldar -- only the Avari, the
refusers, are not, and they likely fell prey to Morgoth long ago. Many of
the Teleri, the most numerous of the Eldar, likely stayed in Middle-earth,
although we don't know that for sure. Some of the Noldor and Sindar
probably stayed as well. And all who stayed eventually faded, which
explains why we don't see them around any more -- although their spirits may
still be present, like ghosts in the woods and
streams.
“I dislike Allegory - the conscious and intentional allegory - yet any attempt to explain the purport of myth or fairytale must use allegorical language. (And, of course, the more 'life' a story has the more readily will it be susceptible of allegorical interpretations: while the better a deliberate allegory is made the more nearly will it be acceptable just as a story.)” (From Tolkien Letter # 131.)
