[burrahobbit]

Your logic, such as it is, is that it is up to the reader to decide the exact content of a given book. In this particular case you are applying it to the question of the greatest elf. You have come up with your own conclusions, which is generally fine, but in this case it goes against the explicitly stated opinion of the creator. I took your logic and used it to determine that it is up to me to determine if Frodo died in the first chapter. This, of course, is a ridiculous proposition. It is perfectly obvious that he lived throughout the entirety of the book, just as it is now perfectly obvious that Luthien was the greatest Elda.