>A solution exists, and is nearly universally implemented: scroll wheels on a mouse, and scroll gestures on a trackpad.

So you didn't read the article huh. The very first paragraph says:

>“Ah”, they say, “that’s what the scroll wheel is for”. My friend, not everyone can use a scroll wheel or a swipe up touch screen.

Or literally the next paragraph about difficulties small/hidden scrollbars cause with other input methods, e.g. eye trackers.