To be clear, I don't think people are actually dumber but the writing level of average internet persons seems to have plumetted off a cliff sometime in the past 10 years or so. sentences are short and read like the assembly instructions for a walmart bookshelf and the vocab and breadth of word choice seems to have shrunk.

it could be an actual shift in language, or it might be a demographic shift; I grew up when using computers for anything but book reports was nerdshit. it may be that the normie takeover has been completed and the dorks with the "smart writing" are simply a minority online now rather than being the average internet shitposter.