As he got older (and more famous) I think he became more reluctant to acknowledge the influence of others.
I agree. I don't think it was so much a matter of personal pride as that he didn't want people to categorize his great works, or to read them with an influence-hunting agenda, in such a way as to become impervious to the enchantment of the Secondary World. He had labored mightily on Middle-earth throughout his adult life and it was pervaded by his conviction and (what we feebly call) his values; it was the making of a story by the exercise of "a kind of Elvish craft," etc. In his "On Fairy-Stories" he regrets the tendency of anthropological scholarship to seek to trace (often rather speculatively) the "ingredients" out of which the rich stew of Story had been made, and into which individual minds had sometimes added their own unique contributions. So when he became famous and people pushed him about "influences" and genre and his possible current events "agenda," he discouraged those lines of inquiry. The interviewer could have pushed him about the goblins in
The Hobbit and their manifest kinship with MacDonald's creatures in
The Princess and the Goblin. It's perhaps just as well that Resnick did not pursue the matter.
Motives for exploring the matter of "influences" may vary. There may be the ignoble desire of the less gifted to cut down the genius to size. There may be the dubious desire of the academic to advance his or her career by Publishing. There may also be the gratitude of the reader who honors the author by seeking to understand better the nature of his or her work; for one thing, this can help to prevent misreadings and misevalualtions of it. For example, if
The Lord of the Rings is classed -- as was done in early reviews! -- with Lewis Carroll's Alice books or is labelled as "super science-fiction," it may seem to "fall short" against canons appropriate to those works. If, however, it is seen as mythopoeic romance -- as THE modern mythopoeic romance -- then it's more likely to be appropriately evaluated and better understood. If we're going to talk about "mythopoeic romance," though, we can set out some characteristics thereof, but we'll need other actual examples. And Haggard's
She is one. But this sort of mental activity is best exerted after someone has loved
LotR in its own right, so that he or she knows it well enough to be ready to talk about it and not just say it's great and everyone should read it. : )
To be autobiographical: I'm sure that much of my own interest in this kind of thing was that I wanted to find more good fantasy. That may be easier now or it may be harder -- easier because so much is now in print in paper or available online, but harder because there's so much more rubbish around than 50-odd years ago. When I read of Tolkien's interest in
She in 1969, in Lin Carter's sub-scholarly "Look Behind" book, I knew that was something I wanted to get hold of, & I did, and eventually I'd read that one half a dozen times, and two dozen or so of Haggard's romances. I'm glad too for blurbs mentioning Tolkien that long ago piqued my interest in Alan Garner's
Weirdstone (influenced
by Tolkien) and William Morris's romances (likely influences
on Tolkien -- for what that's worth).