Why did Legolas set sail for the Grey Havens only after Aragorn's death?

[Galin]

Originally Posted by LadyBrooke

Eldar is a hard word to define in Tolkien works. In various places, it seems to mean the elves that sailed across the sea, the elves that intended to sail regardless of whether they made it, and just a plain synonym for elf.

If push comes to shove, for myself I don't see why the author-published definition should not take first place above 'unpublished' writing -- and I think The Lord of the Rings is clear enough, despite any examples that might be raised otherwise, that technically at least, 'Eldar' does not refer to all Elves, as Appendix F draws a rather notable distinction (among the Quendi the Eldar were as kings). Also, from Appendix F again:

'... and hence it [Sindarin] was the tongue of all those Elves and Elf-lords that appear in this history. For these were all of Eldarin race, even where the folk that they ruled were of lesser kindreds.'

One could push Tolkien concerning the word 'all' here, but shirly Thranduil was an Elf lord, and no Elf appears more 'in this history' than the son of this ruler, Legolas Greenleaf. Unless I'm reading this wrongly...

In my opinion, blood doesn't matter, as much as what the person declares himself to be - after all, we consider (...)

Still, in a given discussion I think Legolas could claim to be Eldarin as well as one of the Silvan Folk, if he thought that the former distinction was relevant... depending upon whether or not a son or daughter of a confirmed Elda can also be said to be Eldarin for whatever reason.

Is the son of a Light Elf himself a Dark Elf because he had not lived in Aman nor seen the light of the Trees? Or is there something outside of the 'definition' that can or might be considered?