I’m old enough to remember when people said things just like this about Apple products: “It’s very nice, but switching ecosystems away from Windows s risky.”
But it still is. As another comment said, only 12% of laptops are Macbooks; it'll remain very hard to replace PC's and Windows in the large corporate and government worlds, thanks to Windows-specific software. A lot of software is moving to a more OS-agnostic platform (i.e. web), and cross-platform applications (like MS Office) are becoming more and more the norm, but there's still a long way to go.
It'd help a lot if Microsoft manages to get .NET applications to become popular on OSX. That's only possible since this year, and it'll probably take a few more years for applications to become properly crossplatform.
