Same reason as iTunes for Windows and the iPod monopoly then. On the other hand, Office for Mac likely has <5% marketshare at most, so Microsoft could legitima

Same reason as iTunes for Windows and the iPod monopoly then. On the other hand, Office for Mac likely has <5% marketshare at most, so Microsoft could legitimately justify less development resources as making financial sense, similar to how Mozilla and Google treat Windows as the primary platform for Firefox and Chrome respectively. On the other hand, I wouldn't be surprised if the marketshare for iTunes on Windows exceeds that of iTunes users on Mac OS X, so there's really no excuse for that particular half-arsed port.