They use upgrading to IE9 as an example. However, many companies are still running IE6 and IE7. Windows XP was replaced in 2006 and it's still pervasive on corporate desktops. 16GB of RAM is $100 and it's useless in the average corporate desktop.
Sorry, but I think corporate IT departments just try to grow large and be as risk averse as possible.
Growing large and risk averse is what all bureaucratic organizations do.
Using IE6 as an example, in my case at least, for that isn't accurate.
In 2002 I installed a brand-new shiny system to replace our then paper-bound order system. Required IE6.
Fast-forward to 2011 - the version I installed is still in use. IE and Firefox latest work 'ok' for the client, but the administrators must maintain a copy of IE6 [1] for their functions. [2]
We didn't upgrade in 2004 because the costs were prohibitive. We dropped support in 2006 because the cost to support our obsolete version went through the roof, and we were going to implement those functions in JDE 'real soon'.
I stopped supporting the system in 2007, and it went to another team, but we're still using the thing, same version, in 2011. IE6 is still required, of course, for the admin stuff.
All of the decisions that force a handful of people to use IE6 were made above the IT level.
In this case, at least, ain't us man.
[1] Or Safari with UA set to IE 7.
[2] It's a shiny pop-up java thing that looked real slick back in 2001.
Sorry, but I think corporate IT departments just try to grow large and be as risk averse as possible.