Why is it so difficult?

[Kath]

Pick up a copy of the Mabinogion and you will experience the same style, slightly distant and 'high', a sense that the text was not written in the same century which produced The Hobbit.

That's exactly right, and reading that book was the only way I got through the Silmarillion. I went from The Hobbit to LotR and from there I tried to go straight onto the Sil but got bogged down by the 347 names beginning with F somewhere in the middle. I moved on to Arthur and those stories and finally returned to the Sil many years later. It was still a struggle to get through it and it certainly warrants a re-read as I remember little of it, but many of the stories were excellent and I personally greatly enjoyed the beginning.