Classroom level is only one aspect of it though; literacy is learned through exposure and various levels. Another commenter mentioned social media, which is probably a factor too. Low effort high volume comments, indifference to proper spelling ("bcuz u can understand me"), more video / image based than text based, different reading habits. Education is part of it too, in theory we were supposed to read X books per year and write a report on them (in practice, even back then we downloaded and slightly edited the reports from the internets).

> even back then we downloaded and slightly edited the reports from the internets

When was this? It being easy to find completed homework on the internet wasn't a thing 25 years ago, so "even back then" seems to not be that long ago, considering this would have been when you were in middle school. Majority of adults today didn't go to school under those conditions, they had to write those reports or copy from a friend, which of course is easy to notice for teachers.

I think it's more that people lose the ability to read and write as they stop doing it when they finish school.

Guess what kind of site you're on

You’re not wrong. But have you considered the difference between mainstream social media (video postings of 15-30 seconds) with HN (share a complex or long article, then have a text debate about it, using sophisticated English)

Your opinion of Hacker News is too favorable

I’m just comparing with Facebook, Instagram and the likes. Admittedly that is a low bar, but compared to them you’ll pick up more on HN.

Because we were talking about the linguistic level, not just the informative level. Not much text on FB or IG, except for the captions perhaps.