Why is Tolkien's work so well known and popular?

Tolkein did it first, his books came out before those others you mention, it was part of the start of the fantasy genre.

When something comes out in 1954 and predates the regular fantasy novels we are familiar with that were all written at least 2 decades after that, yes the original stand alone and above those.

They struck a chord with readers, same as the Narnia books.

Because in the minds of many people he created Fantasy. People had been writing Fantasy long before, even if in the form of songs and myths. But he was really the first person to really get creative and build totally new languages and a setting that felt real. He was also a well educated man who could write good prose.

I liked the Hobbit as a child but LOTRs was a bit of a slog to get through with lots of info dumping - that's how they told stories back then. Now we've found other ways to make it more interesting for the reader, but for some reason, you don't get the same "story" feel. When I read Tolkien I feel like I'm being told a story.

probably cause he was a good writer