The OS X shell hasn't changed terribly much since it was first released. GNOME Shell ("GNOME 3") was publicly designed prior to anyone seeing Windows 8 or Unity

The OS X shell hasn't changed terribly much since it was first released. GNOME Shell ("GNOME 3") was publicly designed prior to anyone seeing Windows 8 or Unity (in fact, Unity started after the GNOME 3 development process began). GNOME has more in common with webOS than OS X, Windows 8, or (perish the thought) Unity.