A good writer knows how to make their reader feel something - utter despair, boundless joy, irritation - even if they haven't experienced it for themselves. Good writing doesn't have to have perfect punctuation or sophisticated language. It just has to be meaningful to whoever is reading it. Sometimes it teaches a lesson, other times it's a warning, and sometimes it is simply an unfettered rant of all the things we can't bring ourselves to say out loud. And not all writing is the same. For example, poetry comes in many forms and often doesn't follow standard punctuation and grammar rules, but that doesn't mean it is bad writing.
Good writing still matters, even with social media. It just may not always be the first thing we see when we log in. Important, unique thoughts can still be shared in a 280 character tweet with no punctuation. Creativity is expressed in so much more than just words through TikTok and YouTube. Facebook and Instagram allow us to connect to others during a time when it's even easier to let ourselves sink into the loneliness and forget there are still others out there.
Good writing will always matter. People will always go back to the classics - Shakespeare, Tolstoy, Bronte. But we can also find good things on social media. We just have to search a little harder for them - or learn to create them ourselves.