Echos of Tolkien?

I recently finished Lloyd Alexander's The High King. (Yes, I know it was published over forty years ago, but I have a long list of books to read.) The High King is the last novel in The Chronicles of Prydain series and won a well-deserved Newbery Award and was a finalist for the National Book Award. More complicated than the previous novels, the plot covers a complex array of battles, betrayals, and alliances that draw in all the characters from the previous books, adding to The High King's sense of richness and depth. A number of Taran's friends also meet their ends along the way which adds a gritty sense of realism to the story. I'm not talking Thomas Hardy here, in which characters die in such tragic and heart-wrenching ways that you can only stand to read the story once--Tess of the d'Urbervilles and Jude the Obscure come to mind, but life is filled with sad losses and The High King would lose much of its power if Taran's life did not also suffer losses. The theme of sacrifice, which figures prominently in the series, comes to the forefront at The High King's conclusion. With the defeat of Arawn, all those descended from the Sons of Don or with magical abilities must depart Prydain, including Dallben, who has raised Taran from a baby; Fflewddur Fflam, Taran's longtime friend; Gwydion, the reigning high king, and  Eilonwy, the girl Taran hopes to marry. Gwydion invites Taran and others to join them in the Summer Country, a place of immortality, as reward for their services. At first, Taran agrees to go but the call of unfulfilled promises and the work that must be done to rebuild Prydain after the wars with Arawn, compels Taran to follow the difficult road and stay in Prydain, giving up a never-ending life with his friends. Eilonwy also sacrifices, giving up her magical powers to stay with Taran. Dallben declares that Taran's decision to stay fulfills a prophecy and Taran is the foundling who has become the high king.

As I read the final chapters, I was struck by the many parallels to the conclusion of Tolkien's Lord of the Rings. At the end of both works, a new king is crowned, Aragorn in LOTR and Taran in The High King. The world of each story enters a new age, the Fourth Age in LOTR and a post-magic time in The High King. An exodus to a land of immortality occurs, the elves sail to Undying Lands in LOTR and the people of magic sail to the Summer Country in The High King. Some are invited to join the exodus, Bilbo and Frodo in LOTR and Gurgi and Glew in The High King. A woman eligible to leave in the exodus chooses to stay and rule as queen with the new king, Arwen in LOTR and Eilonwy in The High King. The ending of Alexander's story is not contrived or forced. It has that sense of inevitability that all great stories have. I'm left wondering what to make of all these parallels. Alexander drew heavily on Welsh mythology for his stories. Tolkien relied on Norse and other traditions. Perhaps the answer lies in the parallels to be found in their respective sources or perhaps there was no better way to end the types of stories that Tolkien and Alexander were telling.