[Galadriel55]

Good question. Lots of room for speculation here.

The stories do seem to reflect the knowledge/experiences/personality of their authors. But only the tone of the stories - the facts would remain the same regardless of author.

But thinking about it, the ME authors only affect the books within the bounds of the legendarium. The real reason probably is that Tolkien wanted to try out different styles and themes, and created the "authors" as an excuse for the new/different style.

Are you planning on speculating about the strictly Middle-Earthian reasons, where the canon is real, or about Tolkien being the ultimate source, and he canon is, however beautiful, made up? It boils down to how you see the legendarium. I see it both ways, differently at different times, and ME-thian explanations work as well as RL facts for me. Speculation? Hmm.