Like if each edition of an ebook had its paragraphs rearranged based on how much time people spent reading them

You are mistaken. Replies to a node should not, and in general do not, depend on each other. Sometimes, of course, a later reply will say something like "As Ovid said above..." - and this can seem slightly strange if Ovid's reply is now below instead of above. But that's extremely minor.

You would have a point if replies in a thread were presented out of order, like:

Jim: comment 1

Jim: comment 3

Bob: comment 2