*WARNING* This IS Techo-Babble
The thing is, that 30% is still a lot of corporate users in particular. Most home users probably abandoned XP by the time Windows 7 came out (maybe some held on after the "Vista Diaster") or have upgraded since.
The corporate environment represents a whole different kettle of fish - Staff training, computer migration and testing to ensure that Corporate Networking Components (Active Directory, Roaming Profiles/Folder Redirection, Group Policy, File/Resource Sharing) are all functioning as they should.
I know in a number of environments, the transition only begun about 2 years ago, and is still no-where near completion, whereas others migrated quickly and efficiently. I guess it all depends on the different applications these networks are used for.
Back in 2009, those corporate folk had the lifting capabilities to push Windows XP to now, so it will be very interesting to see if they have the ability to fell the giant once more, if they should even try.
Something tells me M$ might just push support out a little longer, and end it next year with Server 2003. I know that last time, it was due to end and they (MS) were perhaps saying "No exceptions," although I cannot remember. In China, I think that IE6, MSN (The social-networking tool) and even Windows XP may still be supported. Over there, XP usage rates are still around 70% of ALL computers. Try to get all of them to switch in <1 month!!!
So at least in this regard, the corporate folk have saved home users some money, if they believe M$'s scare tactics. They also saved themselves lots of money.
Like I said before, provided people excercise safe browsing habits and keep a good up-to-date Anti-Virus and Anti-Malware, you should be 100% fine. You don't even need those two things if you are very particular about how you use your computer, or you don't even browse with it (And instead run a File Server from the system).
I've also mentioned before my local Supermarket still run Windows 2000 (which is registered under the old business name too), another two on Windows XP and the "main machine" on Windows 7. That won't change anytime soon, I don't think. AFAIK, our local drugstore might has a mixed bag of OS's from Windows 2000 too. So you can see that there is certainly no issue sticking your heels in the mud - provided you do it right
