Many managers have already switched to OSX for personal use and if they can (including at places like IBM) for work as well. The reliability is unbeatable especially as Windows becomes more and more unintuitive, unreliable and bloated.
The key factor to this switch was porting Excel, and to a lesser extent the rest of Office, to Mac. Even with the reduced feature set, it means non-technical and semi-technical people can now work from a mac. Excel probably runs in virtually all companies in the world today.
If Microsoft were to invest some time in porting Excel and the rest of Office to Linux/UNIX, which are today very user friendly to non-technical users (my mother uses Ubuntu on her desktop, for example), they will give people a way to avoid the high pricing and increasing unreliability of Apple. This should boost sales of non-macs which is good for Microsoft's competitive position, even if these devices are immediately wiped for a new OS.