"a language that doesn't adapt to an ever changing society is bound to be lost", sure, but adapt too quickly and you lose the ability to communicate between groups of people.
There needs to be some compromise where new words are adopted, and changed words are accepted, without flooding the language with garbage. For example, English should still be taught in schools, and English teachers should still have the freedom of correcting the writing kids produce, and taking points off for "mistakes".
Like, if you go pure descriptivist, "it's" and "its" can now mean the same thing. There is no ability to distinguish between their, they're and there. A business email describing a product as "cheugy, no cap" is perfectly acceptable and it's up to the reader to figure it out, because every word is a real word and perfectly valid, and every grammar deviation is acceptable because languages evolve.
Even on social media, I think it's fair to push back on "mistakes" that make it hard to understand something. An error that might take a poster 1 second to fix, might cost the world minutes, as thousands of people each take a few seconds to puzzle out what the OP meant to write.
Languages are about communication, and that can suffer whether the language police are too rigid and forbid any deviation, are too easily bribed and allow for anything.
Certain registers of a language do have different rules, but those also change and are still kinda whatever that part of society agrees with. Business letters that I learned to write in gradeschool in the '80s aren't necessarily the same as I would write or expect to receive today. Ubiquitous, fast electronic communication also through a wrench into things a bit.