Yes, I think one of the reasons people are still using Windows XP is because Firefox, Google Chrome, Opera, and many modern web browsers are still releasing updates for their web browser, and making their web browsers work for Windows XP.
A lot of people mainly use their PC for browsing the web with a web browser, and back in the past like in the 90s people who had Windows 95 installed on their computer were stuck using Internet Explorer 4.0, and had to upgrade to Windows 98 to use Internet Explorer 5.0-6.0.
But, now with Windows XP, and good IE alternatives like Firefox people can use the latest version of Firefox, Google Chrome, Opera, etc without the need to upgrade to Windows Vista to 8, so for people who mainly use their computer to browse the web, they can stick with XP. A lot of the plug-ins like Adobe Flash Player, Java, and Silverlight still work for XP.
A lot of free non-web browsing software like Open Office, Winamp, Gimp, etc still works for XP, so upgrading to a newer version of Windows is not neccessary for many PC users.
I think the XP user names are still high, so I doubt Firefox and other makers would cut off XP so quickly. Who knows maybe these program makers use XP themselves.
I agree a lot of the people who donate code to Firefox may still use Windows XP, so they don't want to buy a new computer to use Firefox, so they make Firefox still work with XP.
Plus, XP users would move to Google Chrome, and other web browsers if a web browser stop supporting XP.
It's funny, because a lot of these XP users are just inept at the Internet and/or computers, and thus they never update anything or get any programs outside of the default Microsoft programs, except for communication and games.
I know, because it's actually significant enough for me to know people in this group...
I think many Vista, 7, and 8 users are somewhat the same, and mostly use Internet Explorer and Outlook/Windows Live Mail. IE8 which is the last version of IE for XP is not very good to use, so I think more XP users switch to either Chrome, or Firefox which is usually in the top 3 of web browsers at different times of the year.
Plus, it is not too hard to find IE alternatives by searching "Internet Explorer alternatives" into Google search or Yahoo, and I think there are links for Chrome browser download on Google.com, and plenty of Google ads for Google Chrome online when you use IE, Firefox, etc to browse the web.
Maybe XP is the best operating system for older computers with only 256-512MB of RAM and a CPU which is 1 GHz or slower while Vista, 7, and 8 won't run on slower computers which still work, but are too slow for newer versions of Windows like Vista-8. A lot of people don't really like upgrading their computer to use the latest version of Windows which can be expensive at $99-199 depending on the version.
XP also is still compatible with a lot of web browsers like Firefox, Opera, Slimboat, etc, and E-mail clients like Thunderbird, and Windows Live Mail which don't use as much RAM and CPU as Internet Explorer 8.
