Yet Tolkien still sold the rights to his works so the things he didn't want would take place. Strange, right? You are using that as a brick wall when in reality it is an open gate. Tolkien enabled these things when he was alive and Amazon is not the first to have created their own version of Tolkien's work. Every work has been a derivative of Tolkien. They all change stuff or create their own lore. They aren't bad because of that.
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It is even getting a second season based on "new" work. One author is dead and one is still alive so it will be based on unreleased work finished by the remaining author.