Do you have any idea what Tolkien studied? LOL, he was definitely not a "modern" man - he was a master of ancient languages, history and anthropology. He knew exactly what he was endorsing.
If you think that ancient Anglo-Saxon and Scandinavian monarchies would be remotely suitable to the vastly different economic and cultural situation of today, I believe you and Tolkien are mistaken, as much as I admire Tolkien.