Uniqueness in mythology

Here comes a phrase too often heard in a host of works dubbed "medieval fantasy":

"This is inspired by Tolkien".

Here then comes the most common answer to demands of originality, from people fed up by Tolkien's mythology:

"This isn't Tolkien. We are copying Howard instead."

In the same way, every horror writer is inspired by either Wes Craven nowadays, with some Lovecraft thrown in the mix. Similarly, every vampire story takes its roots in Bram Stoker or Anne Rice's works, save perhaps Josh Whedon's series.

Why in the world are we unable to create new and compelling mythologies? Why can't we break from those molds? What is the process required to break away from those molds? Are there not myriads of possible mythologies that could inspire breakthroughs in storytelling? I'm stuck myself in this conundrum, for although the core of the story I'm writing is very promising, and the behind-the-scenes aspects of my mythology is somewhat rarely found in stories, the visual impact of my mythology reeks of "I've played too much WoW/D&D".

I want the world-beyond-the-world in my writings to be unique. I have to stare at Neil Gaiman's The Sandman for hours just to convince myself that it is possible.

The difficult part in this is that recipes, by definition, cannot create something wholly new.

So I ask all my readers: how do you manage to create newness and uniqueness in a mythology? Do you even attempt it? And as readers, do you care?

I will attempt originality in a new cosmology, which works within the world I am crafting for my stories. But before I write out my attempts here, I would love it if one of you could answer the questions above, for yourselves, without any bias interfering through my exposed attempts.