Eh, that at least goes back to the days of dial-up (at least).
56k modem connections were 7k bytes or less.
The drive thing confused and angered many cause most OSs of the time (and even now) report binary kilobytes (kiB) as kB which technically was incorrect as k is an SI prefix for 1000 (10^3) not the binary unit of 1024 (2^10).
Really they should have advertised both on the boxes.
I think Mac OS switched to reporting data in kilobibytes (kiB) vs kB since Mac OS 10.6.
I remember folks at the time thinking the new update was so efficient it had grown their drive space by 10%!