Yes, I think you're right, and after all it was Poe who was meticulous when it came to vital aesthetic considerations of mere quantity.

If we took our favorite song, for instance, and made it into a full-length film, the result could not help but be a diminshment of our beloved number, since all the delicately precise harmony we admired would be stretched and distorted, as in a fun-house mirror; the material dispersed in a different medium would become alien, even ridiculous, and merit would turn into its very opposite.

Most films and novels require a certain amount of padding, small talk, if you will; not so with most short stories, and especially not with Poe's, which are super-dense and super-pure, like a poem, or  song.  The man who said, "a long poem does not exist" knew what he was talking about, because no man had such a poetic soul, and strove to put 'poetry' into everything he did.  The quotidian can be more easily filmed than poetry.  If film is art, and not mere imitation, how can it take what already is a work of art and 'make it' into art, since the 'art-making' has already happened?  It is almost as if a quantity of dross must exist in whatever is to be translated into another artistic medium.  Poe's work has so little imperfection, is so purely artistic, that another medium cannot be artistic with Poe's work as its material.