I’m not sure why this post has so many downvotes, because this is accurate. I just started working somewhere that utilizes a lot of technical writing and there are style guides to make sure your writing is in its simplest and clearest form. Text is rated on the Gunning fog index, which uses words per sentence and syllables to calculate readability. Writing for the public is intended to be at an 8 or lower, meaning 8th grade readability or lower. I think many people never really learned to read at higher than an 8th grade level, and the rest get used to never reading higher in their daily lives.

I never really considered the part ESL individuals play into this phenomenon. It makes sense that a nation of immigrants would have a large population who isn’t up to speed with English

It’s a self-reinforcing cycle. If you write directions at too high a level, people don’t read them and call support instead so someone can explain the directions with more and smaller words. So if you’re writing the directions and taking support calls, you have an incentive to try to write your directions at a low reading level to reduce your future support burden. (That doesn’t make you any good at it.) Which, if your hypothesis is correct, hurts the readers’ ability to read complex sentences a little bit in exchange for reducing your support burden by a lot.