The problem is that Google only covers "most of it", so even if it covers 99% of use cases, for that cases where it doesn't, companies still need MS Office.

I worked for a startup that was all OSX desktops and Google Docs. Then when we hit 100 employees, the finance department required MS Office, so they used Office for Mac, then as we grew, they needed real MS Office running in Windows, so they ran Windows in Parallels, then as we continued to grow they moved to full Windows laptops. When I left the company (at around 1000 employees), almost a third of the company was on Windows (mostly in Finance, Sales, and other business departments). And the team supporting the 2/3 Mac desktops was about 1/3 the size of the team supporting Windows.

Though I suppose it's easier for a government to move off Microsoft. When an investor tells you to use their financial modeling software that only works with MS Excel, it's pretty hard for a small company to refuse, but a government has more power to force others to conform to their choice.