I think my perplexity about Tennyson's intent is due to misunderstanding his dedication of the poem to Queen Victoria and Prince Albert, made at the height of the British Empire. I've been trying to understand it as a hymn to empire, when it is actually about the fall of empire - D'uh! So, ok, hit the refresh button and it makes sense, and fits better in my mind as a development of the Arthurian tradition.
The high ideals Arthur requires of 👇🏼