Originally Posted by
Lokasenna
Wagner actually based his Ring Cycle on the Nibelunglied, which is an old Germanic poem. Völsunga saga is indeed an Icelandic text, and both are derived from a much earlier source material, which is now lost (if indeed it was ever codified). Thought there are many similarities, the two versions have plenty of differences, the obvious one being that Sigurđr is entirely absent from the Germanic version, while he is the main character in the Old Norse source.
While I'm sure that Tolkein was familiar with Wagner, the fact that he is considered one of the greatest medieval critics that we have had, who lectured and wrote extensively on Old Norse and Anglo-Saxon literature, would suggest his great familiarity with the source material. One case in point would be the latest thing they've published (Sigurd and Gudrún) from his files - the man was writing his own Eddaic poetry, extrapolated from the source materials in terms of content and style, to fit into the gaps of the poetic canon surrounding the prose Völsunga saga. As far as I am aware, no one else has tried that, and if they have, they certainly haven't advertised the fact.
That said, he borrowed some motifs from Völsunga saga, but they're hardly uncommon. Aspects like the reforging of a broken sword, or the idea of a magic ring, are extremely common tropes in the Fornaldarsögur. Other bits of his material are startlingly original in their reinvention and reapplication.
As for your personal opinion on the quality of his writing, then I respectfully disagree, and I freely acknowledge that he won't be for everyone's tastes. But I honestly think that a comparison to Star Wars is to do it a disservice - to think of it as a mere escapist fantasy is to ignore the subtlety with which Tolkien uses his source material and his own imagination. His works are as much an academic exercise as they are a literary one.