Why would that matter? The largest single part of the market is Office for Windows, so that's what they targeted first. Google employees are likely using Google Docs for most things, anyways.
I was looking into this a while back, and I'm curious: does anybody know whether it's even possible to develop a sophisticated add-in for Mac Office? MS added VBA support back to Mac Office 2011, but VBA can only do so much. On Windows, sophisticated Office plug-ins are typically COM add-ins, which can be implemented in C++ or .NET and thus can pretty much do anything you want. Those are obviously not cross-platform, though. I believe Mac Office also supports AppleScript, but it's not clear to me whether that's any more powerful than VBA.
I'm sure they have some Windows installations around for Chrome and web compatibility testing. I wonder would happen to Google if they only made products for Google employees.
