> The first iMac was much more compatible with PC peripherals.

I could be remembering wrong, but this sounds like revisionist history. The original iMac was compatible with USB (and relied upon it); most PCs didn't come with USB ports, and most peripherals didn't support it. Since USB is a universal standard, however, it gave manufacturers an opportunity to make one device that supported both systems (vs. making one that supported Mac-specific printer ports and parallel ports).

This was part of the appeal of USB in the first place, but when the iMac was launched that was not a huge selection of peripherals that suddenly worked everywhere.