Like art, music, fashion, and most things, the answer is that style evolves. If you look at books that were written 50 years ago, you can see right away that the way in which information is presented is a little different. If you read books that were written 100 years ago, some of the reading is difficult. Not difficult because the information itself is difficult, but difficult because of how the author lays it out. It's simply written in a different way than how we would organize it today.
If you try to read Shakespeare, it's nearly indecipherable, although some love it.
The way in which we organize information changes with technology. If you've ever gone to Washington DC, and seen some of the handwritten documents written by the founders, they're written longhand in ink. It's amazing that they could write entire sentences that are lengthy, complete, and complex without having to cross things out
and do lots of editing. They likely learned to write - and think - in this way.
Today, youngsters communicate primarily by texting. Texts are short - not lengthy enough to get into complicated thought. On the other hand, when I went through school, we had handwriting classes, and took "typing" in High School. My generation focused primarily on the mechanics of writing; not on its' content.
Despite texting, I've seen compositions written by High School kids (mine) that are far superior to the kinds of things that I wrote in High School. Their teachers got them to focus on the structure of expression, not on the mechanics of writing.
And today, computers remove ALL of the mechanics from writing: we get infinite "do-overs." We can write what we think, and go back many times to edit it with NO effort. This is not at all how our Nation's founders worked.
It makes me appreciate how brilliant some of them really were, and how fortunate we are today.
Also, today, everyone can read and write. And anyone can make their writing visible on the internet. Over a million people write books every year. Are any of those books Shakespeare? Probably not. But surely, some of them are great.