I never liked Tolkien, though I have only read the Hobbit and a few parts of Lotr. But I was surprised to read here that he is supposed to be critically acclaimed; if anything, at least before the internet era which diluted the meaning of what a critic is (or, if you will, threw shade on the validity of examining whether there are any prerequisites profession or university-degree wise to count as one), Tolkien was never said to be liked by literary critics.
And historically he did overshadow some actually serious writers of the fantasy genre (which at the time wasn't distinct from a subtype of romanticism), like Lord Dunsany (very popular in his day) and Arthur Machen.