Not A Prince...

[doug*platypus]

Interesting point about the immortality of Elves being a factor in Legolas not being referred to as a Prince. It makes sense, since maybe he would never become King. Of course, convention in our own world and with the Noldor shows that there can be Princes who will probably never be Kings. Prince William and Prince Harry (although I'm no expert on the Royals). And the many, many Princes of the Noldor. "Mirkwood is different" seems to be the likeliest answer, that or "Legolas wasn't like that".

Personally, I think that Oropher (let''s just say he started the Woodland Realm in Mirkwood without arguing whether it was him or Thranduil) became King because he was both Sindarin, which is "higher" than the Silvan Elves and because he had some leadership qualities. What they were is practically a mystery, but I'd take my chances on overbearing power.

Interesting, although it wouldn't really explain why Cirdan was a Lord and not a King. Maybe the only difference is in ambition, or vanity. The leaders of the Elves from Cuivienen (Ingwe, Elwe, Olwe, etcwe) must have been chosen on innate abilities. Maybe fate or destiny had a role to play there. Were they created noble from birth in some way? Like it or not, Aristocracy is all over Tolkien's world.