It's also possible that the method of communication is just changing. I've found that often I have more trouble communicating in written form than conversationally, and I wonder if that's because of zoom and video essays, not to mention shorts / TickTok becoming more prevalent. I've also had my writing degrade just because I don't have a place or reason to exercise it as much. So what I'm writing is perhaps less comprehensible because it's more like a stream of consciousness.
Or more likely it's both - people don't do long form or even "hard" reading anymore, and so find more complex text incomprehensible.