Comment: General upgrades vs IE6 (Score 1) 614
In terms of Stability, with a capital S, Microsoft hit their height with NT 3.5.1 (mainly because an application that wasn't specifically engineered for it just wouldn't run on it, but still). For a simple office that only needs file and print sharing Netware 3.12 or 3.20 really was good enough. In office applications I had thought for years that Word 6 or Word 97 (matter of taste) did everything anyone could reasonably need to do. My * on it now is I don't know Word 97's track change and compare capabilities, but I do know that went downhill from Office 2003 to Office 2007 and 2010... And I won't even more than start on this whole insane idea of getting rid of the menus (fortunately alt-e, s, t still works in Excel...).
There really were two points in the OP. First is software in general, and really there is no need to upgrade for upgrades sake in many cases. The second point is IE6 in particular and the security problems inherent therein, but you can solve that one by running a modern version of Chrome or Firefox even on XP... My company generally doesn't care what you install as long as it doesn't require administrator privileges (I left IT support many, many moons ago now), and so the last time I had a website that IE wouldn't load properly I installed Chrome...
To the point of applications specifically engineered for IE6 - a company that does that deserves what it gets in the way of broken support and being hacked. IE 3 was originally the more standards compliant browser back in the browser war days. If you are engineering a browser based solution that is not standards compliant, you have sewn the seeds of your own doom.