You have to go back further in time for the analogy to make sense. Which platform was Powerpoint originally written for? Seems crazy that it was written for the Mac now that it's so associated with Windows and Microsoft. Even the fact that Adobe Photoshop was a Mac program first seems a bit unlikely as Adobe has been treating the Mac as a second class citizen for a while.
They're basically predicting the same early lead then loss of market share, then mindshare will happen again, not saying that it's already happened.
Also, note that the "Mac users spend more money on software" argument was very popular, even (or indeed, especially) in the bleakest of dark times for the Mac platform. Meanwhile, software that was given away for free and/or relied on network effects (Skype, Firefox, various P2P things) generally started and focused on Windows, because that's where the people were.
They're basically predicting the same early lead then loss of market share, then mindshare will happen again, not saying that it's already happened.
Also, note that the "Mac users spend more money on software" argument was very popular, even (or indeed, especially) in the bleakest of dark times for the Mac platform. Meanwhile, software that was given away for free and/or relied on network effects (Skype, Firefox, various P2P things) generally started and focused on Windows, because that's where the people were.