I don’t think it’s hyperbole to argue that the Mac probably wouldn’t have survived without Office, and possibly without a good version of Office. And in 1997 Apple wouldn’t have survived if the Mac platform hadn’t made a resurgence. Apple’s own iWork suite — Pages, Numbers, Keynote — didn’t ship until 2005. Microsoft Office singlehandedly kept the Mac as a credible platform for classic productivity apps for 8 years.
I disagree with John Gruber that Microsoft Office was key to keeping Apple alive in the late 1990s. Definitely Microsoft investing in Apple having Office programs on the Macintosh helped Apple. But the thing is Microsoft Office, particular Microsoft Word on the Mac sucked compared to Microsoft Office and Microsoft Word on Windows back then. Among other things, if you used Microsoft Word on the Mac and then sent the file to your Windows computer, there were problems with the compatible format. I hardly ever used the Office program on the Mac because I was worried that the Word file would screw up the format when I opened it on Windows.
For decades I have been using Windows at work (for my day job) and at home using a Macintosh. And only in the last 10 years or so has using Microsoft Word on Mac worked well with Microsoft Word on a Windows computer. Back in the late 1990s people who really wanted to use Microsoft Office were definitely getting a Windows computer. No one in enterprise was using a Mac back then if they were mainly using the Microsoft Office. People were getting the Mac because they were enthusiastic about it or because they were working on media, like with video or photos or web etc. For me, I knew that Office sucked on the Mac for many many years. Microsoft Office was so bad on the Mac for so many years that most people wanted to use a virtual computer on their Mac to run Windows and Windows Office. That is how bad Office on the Mac was.
Now the Office Program on the Mac is much better. But I would say that is during the past 10 years. And it is certainly much better on iOS and on the iPad.