IT departments in big companies love stable, homogenous platforms. buy an iphone anywhere on this world, it is exactly the same. same OS, same apps, etc. the upgrade path is known, predictable and again, completely global.
hence the success of the iPhone in that space, killing off RIM. hence the success of iPads, killing off classic Windows tablets and even notebooks. and suddenly you see macbook airs popping up in meetings and airport lounges. because once you're on iPhone and iPad - why not take the plunge? a macbook air is the same anywhere on this globe...