[horatio]

I faintly remember that the last section of the Silmarillion dealt with the Third Age in a dozen of pages or so and this text neatly illustrates what you just pointed out, the difference between the "canvas sizes" of the epic LotR and the mythological Silmarillion.
Overall I like this very pattern you already described, how everything was larger in the First Age (lamps - trees - silmarils - White Tree of Gondor in the case of light or creatures like the spiders) and how stories get repeated, i.e. after Morgoth came his little brother Sauron and after Beren and Luthien came Aragorn and Arwen. Perhaps I like it because Tolkien doesn't it make feel cyclical (although it is) or forced.