Assuming the usage data is from Windows 7, the nonexistent usage of menu is probably largely because the menu is entirely hidden unless you know that hitting 'alt' brings it up. And that is a much newer hidden feature (Win7 era, maybe Vista with early signals in XP) than context menus (at least since Win95).

Besides touch-friendliness, ribbons have huge benefits in discoverability. People can't use features they don't know exist; ribbons organize features into browsable, meaningful panels so they can be found, related to each other, and used. The article seems to entirely miss this point.