prescriptivist rules are based on major over-simplifications of how language works.
All rules and explanations are simplifications. Nobody can honestly say how language, or anything else,
really works.
Simplifications are created to perform functions. The criterion for accepting or rejecting a simplification is: does it deliver the goods?
In the case of prescriptivist rules of grammar, the "goods" are precision and comprehensibility in thought and communication. They should function like a car manual does for a driver. If the rules are too vague or general or outdated, they should and will be discarded. But to reject prescriptivist grammar because it is a simplification is like throwing away a bowl of chicken soup because it is not a cauldron of bouillabaisse. Purpose and function must be taken into account.
One of the great pleasures of reading Achewood is drinking in with the mind sentences that are not only grammatically rich and well-constructed but which stretch the language, make it bounce around and party a little.
Let's face it: decades of ignoring grammar instruction in American public schools has made good writing increasingly rare. Have you read Time magazine lately? It's crap. And how often do you hear someone struggle to express him or herself, and, failing to find the right words, fall back on tired cliches and stale media phrases to express his or her thought? We turn to an obscurish webcomic for prose that is rich and displays a love of language hard to find in the dry forest of American media.
Americans aren't stupid, they just lack the right tools. Who will provide them?
Ezra Pound:
The individual cannot think and communicate his thought, the governor and legislator cannot act effectively or frame his laws without words, and the solidity and validity of these words is in the care of the damned and despised litterati …when their very medium, the very essence of their work, the application of word to thing goes rotten, i.e. becomes slushy and inexact, or excessive or bloated, the whole machinery of social and of individual thought and order goes to pot.
This quote is from a review of a newish American novel, a review that is worth reading if you care about language.
http://www.theatlantic.com/doc/200712/vietnam