Why are so many medium to large enterprises still using Internet Explorer 6? Is there some secret ultra valuable feature or cost reason that has extended its life? What are the most common excuses you have been given?
The biggest one I hear is testing legacy code against a new version. With so many companies having internal web applications which they haven't touched for a while, they often site system instability and the high cost with testing all the production systems against a new version.
It's also difficult to get any large organization to do anything faster than a snails pace. Upgrading in these places often takes years.
Many organizations are looking at this from the other direction. Absent at least one compelling reason to upgrade, they see no reason to do so. And this logic is hard to argue with. An upgrade will cost money, will trigger problems, will break things, and will be a distraction.
Why fix what isn't broken? Particularly when there is a whole bunch of stuff that is broken, a smaller budget than last year, and a number of empty tech staff positions because of a layoff or hiring freeze.
I don't necessarily agree with this posture, but I understand it.
Cost. Always cost.
Never had to endure it on my own machine, but certainly I've encountered this at a number of clients (typically government and large financials) where IE6 is actually just a side effect of having hardware rolled out in 5 year+ batches. Monolithics like this create massive management problems for themselves by buying and rolling out their upgrades in chunks, never at the top of the curve anyway (too expensive).
There are many internal and vendor supplied web applications that depend on the silly way Internet Explorer 6 does business (much as the public Internet used to). It's quite the struggle to get everything upgraded appropriately, and it's a real pain to have users on different versions. I've personally spent about one hundred hours upgrading one medium sized internal web application to support Internet Explorer 7, and that doesn't include my team testing time, and the users testing time, and the support time of having to roll users back when they were upgraded early! This is just one application in a large corporation. The short answer is it's not as easy as you make it sound and users really don't like losing their functionality at all. Welcome to corporate IT. If it were easy they wouldn't pay us.
The root of the issue is that big enterprises made assumptions that IE was the only game in town when it came to web applications, and that Microsoft would stand by its products and support backwards compatibility. Now these companies are stuck with these big, hard to solve problems that cost alot of money to resolve.
The first issue, assuming that IE6 was the only game in town was a reasonable assumption back in 1999-2001. Mozilla wasn't yet viable, Netscape had sucked for years and was dying and Microsoft was "it". Actually, IE is still the only game in town for big enterprises, since Mozilla still isn't (and probably will never be) viable in the enterprise and Chrome isn't quite there yet.
The latter item is IMO, a betrayal of the folks who invested serious money into Microsoft's flawed technology directions (ie. ActiveX, the crippled Microsoft JRE) of that era and is a harsh example of why locking yourself into a single vendor's technology stack is a risky proposition.
Microsoft's discontinuance of the MS JRE forced enterprises to move to Sun Java or an alternate client solution, and the retirement of Windows XP will drive everyone away from IE6.