Ignorance is one of the easiest things in the world to correct. But I get what you're saying. If I were to provide my own counterargument, it's that the "language of the educated" is far more likely to extend and buttress the beauty and utility of a language than the "language of the personal ads" and that Latin died out because it wasn't being taught to the people. Now that we're teaching people "the language of the educated" we're making it available to the masses.
Here's the problem: it takes scholars a generation or two in order to reach consensus about anything literary. Nobody is a genius while they're alive; you will never see a literature class pulling anything off the NYT Bestsellers' list to teach. From the perspective of the student, the only examples of literature and language held in high regard are old and dead and therefore irrelevant. From the perspective of the teacher, exposing students to old, dead but brilliant works of literature helps them appreciate it more than if they didn't get it at all and hopefully that appreciation will rub off on them as they create tomorrow's literature.
Really, one side is saying "I hate peas" while the other side is saying "peas build a healthy body." Neither are wrong. I'm more of an "I hate peas" guy because my mom's parents were Harvard/Radcliffe while my dad's parents were blown off their farm by the Dust Bowl and never finished 8th grade. I can still imitate my mom's parents' inflection and manner of speech; it's an extremely pompous dialect that offends anyone who isn't monied East Coast. I can imitate my dad's parents inflection and manner of speech, too, but I also remember their wisdom, their simplicity, and their insight into the world. And lemme tell ya - there's a reason I tend to deliver my hardest truths with cuss words and misappropriations of language.
People pay closer attention.
If you say something smart while sounding like you went to Harvard, people tune you out. If you say something smart while sounding like you just got off a tractor, people think you're sagacious. Not just because they assume you should be stupid - but because they understand you.
It is the easiest fucking thing in the world to put together a well-constructed, erudite sentence that says fuckall. When forced to take an English class in college I would often construct words and arguments in such a way that they actually said the opposite of their face value to see if the TA would notice. He never did. When you can stack words like a legal briefing you can get away with murder; there's a reason graduate theses tend to be written like a build-your-own thesaurus kit.
It's harder to hide your ignorance in simple language, which makes your knowledge come across more clearly. But the art of using simple language well? Yeah, they don't teach that. They teach you how to navigate byzantine jargon so that you can snow undergraduates with it.