Почему Кольцо Тьмы не Властелин Колец?

Why is Nick Perumov's Ring of Darkness never canon to The Lord of the Rings? Anyone who has spent some time communicating with representatives of the Tolkienist subculture knows that among fans of Tolkien's work in recent years, various "continuations and additions" based on events and characters from the history of Middle-earth have become popular. It is also known that all these fanfics have long been divided into canonical works and apocrypha. The name of the first group of works speaks for itself. Apocrypha differ from them only in that, taking the original as a basis, they rethink its content, interpreting the meaning of the original in their own way...