From Lovecraft to Black Sabbath

The album debut of black sabbath had a song called "Behind the wall of sleep", ending like this:

"Take your body to a corpse. Now from darkness, there springs light. Wall of Sleep is cold and bright. Wall of Sleep is lying broken. Sun shines in, you are awoken"

Let's now take a look at H.P. Lovecraft's short story "Beyond the wall of sleep" :

"...All this he tells me - yet I cannot forget what I saw in the sky on the night after Slater died. Lest you think me a biased witness, another pen must add this final testimony, which may perhaps supply the climax you expect. I will quote the following account of the star Nova Persei verbatim from the pages of that eminent astronomical authority, Professor Garrett P. Serviss:
"On February 22, 1901, a marvelous new star was discovered by Doctor Anderson of Edinburgh, not very far from Algol. No star had been visible at that point before. Within twenty-four hours the stranger had become so bright that it outshone Capella. In a week or two it had visibly faded, and in the course of a few months it was hardly discernible with the naked eye."

There's is nothing new there, in that BS was influenced by such macabre works. But what i'd like to focus on is the difference here between the slow fading of the star, meaning also of the supernatural event, in opposition to the rude awakening in the BS song. Nothing to say, but questions :

A statement on fiction? The slow fading of a story, in our minds and the abrupt ending of a song? The rude esthetique of rock, versus the one of literature? As it seems the group has taken the themes and the style developed by Lovecraft, and accelerated them, all along.

Also, and weirdly, the song by BS seems to have a much more happy ending than the Lovecraft story. Or is that so? In fact, it seems as if the return to darkness, in the Lovecraft story, is a reassuring thing, because it ends the inexplicable event of a shining star. Here, the drakness is good. On the other end, the bringing of light in the BS song seems like a rough ending, as if the dreamer was against his will awekened, as if the fiction ended with much despair.

Should we say the song and the story complete themselves? The story longing for darkness, and the song telling how sad it is to leave it, and maybe asking secretly to return to it?