> And if your text exceeds what can fit in multiple columns on a single screenful, scrolling also becomes awkward, because you'd have to scroll exactly to the next screenful to have any consistency.

That used to be a solved problem, before every website started to include multiple oversized "dickbars" floating over the real content and taking up 15+% of the available vertical space. Pressing the "Page Down" button on a keyboard would scroll down by exactly one screenfull. We also used to have scrollbars that on most operating systems would let you scroll down by exactly one screenfull with a single click.