Yes but not in the way you think
What really threatens IT is a combination of Google and Apple.
Goggle provides all of the core enterprise services in a cheap, reliable and easy to administer manner. Going Apple on the desktop relives the burdens of Windows administration, and the Apple store/genius bar relieves the issues of equipment failure diagnoses and replacement.
I have successfully run small development companies (up to about a dozen employees) with no IT person at all. What little admin was necessary i could do as CTO. When we needed to test under windows/IE we simply ran a virtual Windows session on the Imac.
But if you rely on windows as your primary business environment, then you need a full time babysitter to keep it functioning.
