Large organizations create enterprise IT infrastructures that are homogeneous in the extreme. This is a form of self defense. It's hard to support users when there's no boundaries, not to mention more expensive. There's a hidden cost to this however. Here's a quote from a recent article on the reluctance of IT vendors to put Firefox on the desktop when they sell to corporate IT department because of this very issue:

Mike Hong, manager of Special Purpose Systems Inc. (aka Computers & Applications), a Bellevue custom solutions provider, said, "Nobody wants to put something on, whether free or for a price, unless someone asks for it," Hong said.

"Corporate America is sometimes used as a guinea pig when new technology comes out. IT departments have been used for that and have run into problems and spend times fixing errors and bugs, and most of them are shying away and waiting until everyone has run through it and taken the bugs out," Hong said. "A new technology is not necessarily what corporations really want. Consumers want new toys, but corporations don't want them. They have to expense for bugs, for support and for implementations," he said.

From Resellers Not Embracing Firefox Despite Its Popularity
Referenced Mon Dec 20 2004 14:56:59 GMT-0700

The interesting thing to note here is that corporate IT users are unable to use many of the more innovative products and applications that consumers use everyday. Does this put them at a disadvantage? Maybe. A better moral, perhaps, is that if you're an IT vendor hoping to sell to the Fortune 2000, then you're better off with a hosted application than with something that has to be downloaded and installed. Touching the desktop is becoming more and more difficult everyday. Bypass that and you're more likely to make the sale.