Well, one of this points I was trying to make, since the Windows desktop has been around so long, and vetted, is that there are lots of applications (some pricey) available that let you lock down the desktop really easily. Like it or not, the Linux desktop isn't as mature. Even though, as I have learned in this thread, there are programs, like for Gnome, to lock down aspects of the GUI, they are open source projects not projects made by money making corporations.
As Linux geek myself, this doesn't justify going with Windows in my mind, but to a business, its all about reliability and support. Try to convince your CTO or CEO to go with a Linux desktop and lock it down using open source tools and hire expensive and expert Linux Admins, while the other guy arguing the Windows side simply says "People have been locking down Windows for years, and I have negotiated prices from 5 vendors for their lockdown software, and MS is willing to give us support to help us lock down parts of Windows for deployment in our enterprise as well".
It goes along with the whole notion, no one ever got fired for buying Microsoft. It's the same reason Red Hat is doing so well. They are a company that makes money and offers support. This is why my former company went with Red Hat Enterprise Linux, instead of Fedora or Cent OS, which is basically the same. We virtually NEVER use the support contract with Red Hat, but the business always want to buy the "paid" version just in case. This doesn't exist with Gnome or KDE. But if you have an issue with the Windows GUI, call up one of those many Vendors who sell lock down software or call up Microsoft. And for $100 a ticket or whatever they charge, they will be happy to tell you how to piss off your employees even more when they have to call IT in order to change their classpath for Java on their machine, because that tab in the system properties gives an "Inaccessible, Please Contact Your System Admin" when you click on it...