You could ask the same question about any browser, Chrome, Firefox, Opera, Safari, etc. They all release updates and the updates are rather frequent. Why do they do this? Well, improved security is certainly one reason, one which should all be mindful of. Performance enhancements are often mentioned by the browser makers as a reason. Another reason is compliance with changing web development standards.
So, I have to take issue with your comment that "there is little need for such users to use anything above IE version 8. Or even version 7." By the way, the title of the article, which you used as the title of this forum discussion, is misleading. The author is basically saying some internet users are still using very old versions of browsers, not that those old versions are actually coming back.