Outside of the PROLOGUE in which Tolkien goes over the history of the Shire, he never assaults the reader with world-building. It's all introduced gradually, as it should be, and often through broken references that aren't elaborated on in paragraph after paragraph of peripheral exposition. It's the opinion of a poor reader.
That firm deterministic view makes every single person, animal and insect a chosen one anyway, so it doesn't matter. Frodo is not singled out by anything but chance, or what appears to be chance to the inhabitants of Middle-Earth.