Back in those days the first wheeled mice were fairly expensive. It's now almost impossible to find a mouse without a wheel. This makes scrolling more comfortable and much smoother than using the scroll bar (the old-fashioned way). We were continually adjusting our eyes as to where they should focus amongst all those fits and starts.
I tend to think that the wheel also makes the longer page easier to read than multiple pages -- you don't have to find the "Next" button and go through everything needed to click it. And then don't have to adjust your point of view and find your place on the new page.
And if the navigation isn't set up well, when you're six pages deep in an article and want to go back...