During its first decade, the Mac offered clearly superior usability compared to competing personal computer platforms (DOS, Windows, OS/2). Not until Windows 95 did the PC start to approximate Mac-level usability. Despite this Mac advantage, PCs have sold vastly better in every single year since 1984, and the Mac has yet to exceed a single-digit market share.
The Mac’s miserable marketplace performance seems to pose a strong argument against usability. Why bother, if it doesn’t sell? The counter-argument is that usability is the only reason Mac survived.