I remember marveling (in horror) at the page-long sentences I was encountering while reading James Fenimore Cooper in junior high school. While we were able to understand what was written, that was the extreme, at least in terms the literature to which we were exposed. When writing our own essays and theme papers, the rules were “no short sentences” and “no ‘to be’ verbs.” In short, you needed just a little Cooper in your blood to successfully write to the satisfaction of the typical English teacher.
That probably sounds like the Dark Ages to some. While it is accepted that all languages change over time, the past 40 years, and more accurately, the last 10 years, have seen great changes in informal English, if not also in formal English.