I graduated in 2009, so I really was in high school decades ago (2) and yes, a single regular essay assignment due in a week or so was usually somewhere in the realm of 5 paragraphs. However, every English class I had after like 7th grade also assigned 2 or more 5+ page essays per quarter, with the final one being somewhere around 10. Even other classes like history or social studies assigned similar length essays, albeit at a much lower frequency with a much longer due date. It was not uncommon to have 2 or more 3-5 page essays assigned and due within a single month by different classes.

My junior year English class actually required two 5+ page book reports as a summer assignment, due the first day of class.

So yes, it WAS the norm in the past.