You still have a lot of people walking around on this Earth from the "640 kb ought to be enough for anybody" era and beyond, which means we're at well over 43 y

You still have a lot of people walking around on this Earth from the "640 kb ought to be enough for anybody" era and beyond, which means we're at well over 43 years of kilobytes = 1024 bytes. That is an awful lot of inertia, particularly when this problem was mostly just caused by disk manufacturers "rounding up(?)" to 1000 bytes for advertising purposes. Before that abuse everyone could communicate perfectly fine, even though it probably made a certain kind of pedant annoyed.