Unsupportable. Tolkien was only concerned with giving England a distinct history. He probably didn't care about Europe and hated everything French.
Almost everyone assumes Middle-Earth is Europe. Try holding Tolkien's famous map of Middle-Earth up to a mirror to see that it is really strikingly similar to North America, too similar to be a coincidence. In fact, he got a lot of his Hobbit surnames from actual family surnames in, iirc, Kentucky; Baggins included.