Although it's like an established fact that Microsoft Windows has a market share of more than 92% and with the recent release of Mac OS X Snow Leopard, Apple has gained 8% of market share, there are other reasons majority of the CIOs
Nearly all the business users can't and don't make a change just because of the bells and whistles of a Operating System. Hardware compatibility and new user training issues are the first that CIOs have to consider before making an OS swith.
And it's a situation that looks unlikely to change. A recent poll of the Silicon.com CIO Jury found that none of the IT chiefs surveyed said the release of Snow Leopard will prompt their businesses to adopt Apple desktops.