The PC was still in its exponential growth phase during each of these transitions. So the total number of computers built with 5.25" vs. 3.5" drives likely dif

The PC was still in its exponential growth phase during each of these transitions. So the total number of computers built with 5.25" vs. 3.5" drives likely differed by at least a few orders of magnitude. Today's USB/SD-only devices outnumber all of the previous generations combined by several more orders of magnitude. Fewer computers means fewer software releases and fewer files that warrant rescuing. I think there was just dramatically less stuff to copy.