Languages change, so is this a problem? Well, it is if the resulting text no longer says what the writer intended to say
Why do people not care about language?
I suspect most of the time it is because people feel it's not worth their time.
In text/instant messaging conversations, people get straight to the point.
E.g., "lunch at 12:30, meet at Panera?" "can't do 12:30, how about 1?"
No "beautiful language," no real need for AI, most people just type or dictate it, the words say exactly what you mean.
Then there are emails ... you have to write more words than are absolutely necessary to say what you really want to say. Instead of simply saying "review the attached report, check numbers on page X, send revision or confirm the numbers are good by COB," most people feel compelled to provide context about about the report, explain why they want the numbers on page X checked, explain why the COB deadline is important, etc. Now that you have to write more words than you believe are necessary, the urge to delegate to AI to generate those extraneous words for you gets a little stronger.
Then there are letters, academic papers, presentation slides, formal reports, books ... you need to put in more and more extraneous words than those necessary to convey what you believe is essential.
Take academic research papers, for example. Instead of just writing your method, results, and conclusions, most journals/conferences expect an "introduction/background" section, an abstract, a conclusion section, maybe a section on "why you think your stuff is new/important" ... Now you have to repeat your key contents a few times (e.g., your key results may have to appear three times -- in the abstract, in the result section, and in the conclusion). The introduction/background section is mostly you recounting someone else's stuff, little to no originality. With expectations for all these extra words that do not speak to what you really want to convey, the urge to delegate to AI gets stronger.
Similar incentives structure for corporate reports/papers/slides. Often lots of boilerplates, lots of fillers because the template says so, because of policy, lots of hedging and disclaimer language to CYA, etc. The urge to delegate to AI gets even stronger.
It just gets worse as the documents get more formal (e.g., regulatory filings).
I don't have a solution for this. I hope people learn to focus their energy on manually drafting/tweaking the parts that are most important, the parts that convey novel/original things, and that people learn to identify and focus these parts when they look at written communications. The rest will continue to exist because systems/institutions require it or because people expect it, and I am resigned to accept those formal/performatory bits to be overtaken by AI slop.