Middle school used to be called grammar school. Did the name change lead to the reduced emphasis on grammar or did we stop teaching grammar and therefore change the name? Chicken? Egg?
In any event, it's concerning. People read and write more now than ever before. The rise of social media and new technology has made reading and writing even more constant daily encounters than ever before. However, the prevalence of our textual encounters has also made them shorter. Increase frequency, decrease length. As a result, our attention spans are shorter, our exposure to long written works less, and our engagement with edited, published, excellent writing is practically nil. Even a perusal of frequently-visited websites reveals a dearth of correctness in the written word.
I do realize that some aspects of correct writing can seem arbitrary--what gets capitalized why, where do the commas go, why does spelling matter if you can figure it out--but the truth is the more correct our writing the easier for other people to read and understand it. If our current goals are to communicate quickly, then correctness should remain a value since it is an asset to efficiency--limiting misinterpretation, miscommunication, rereading, question-asking, and myriad other complications resulting from poor writing habits.
I recently gave my students an exercise in which I removed all the punctuation, including capitalization and periods, from one page of text. It seems that this may have been the most effective way to demonstrate the importance of these small tools and how challenging understanding writing would be without them. It's hard enough to understand people's writing as it is! Without the tools of voice and body, writing can be flat and unclear. Tone is challenging to judge, main points are hard to distill, and one must actually follow the meaning of the words themselves.
It may not be important to teach people parts of speech or sentence structure in the same ways as we've done in the past, though having this vocabulary does make it easier to discuss problems and point out errors, but even if we let go of the "grammar" in grammar school, we have to continue to think about how the written word can best communicate our ideas to an audience. We can lose the specifics, but we cannot write in isolation--we cannot lose a sense of our readers. And the clearer, and more correct, our writing is to our readers, the more effective it is.