...or rather, grammar operates as a self-fufulling prophecy, an arbitrarity that makes itself valid through an asserted and thus assumed solidity; an active tautology that proves itself. --Why? Just because it is.
In other words, the illusion of a descriptive order inherent in the workings of knowledge masks the operation as grammar as a prescriptive, overlaid imposition of post-facto analysis that then tries to worm its way into the center, outside masquerading as the inside.
I'm aware that the previous paragraph holds a lot of dangerous assumptions - or at least dangerous from a poststructuralist viewpoint - of seeking the 'true' nature of grammar, the notion of 'layers' implying a core essence lying underneath to be unearthed in some archeological expedition, the primacy of something that occurred before vs after, this seeming distinction between inside and outside.
But: the existence of an illusion implies a generation of a new meaning, but doesn't necessarily eliminate the original object to be considered. A distortred windowpane generates a new image, does not eliminate the outside. Is there another danger in this analogy again, or the presence of a real essence grounded in the example of nature, architectural creation vs natural creation, etc? Probably.
Anyways. What I mean to say is that the assertion of a orderly, rational grammar of language as existing as the structural underpinnings -- grammar as base and language as superstructure -- is really a myth, but one that threatens to become demythified, not through any "depoliticizings" that hide its mythical nature but due to a belief in such a myth that realizes myth, denatures it. A prescriptive theory masquerading as descriptive, and widely believed in, closes the gap between assertion and description. Subject verb object constructions, due to a linguistic majority's (or, of a majority of a valued minority class - the educated) adherence to grammatical rules, based on an prescripted argument for SVO structures, gaining authority due to majority adherence, and so on. This is how it really is, and you should follow these assertions; people follow these assertions because this is how it really is.
Simulacra are perhaps the greatest example of a self-fufilling tautology.