It's a good idea to create a new browser that updates automatically every few weeks like chrome rather than IE, which normally can't update automatically because of corporate policies.
Older IE got updates through Windows Update. The last IE version for WinXP was IE 8.
If IE 12 doesn't come with a transparent IE compatibility mode and just starts a IE 11 window, corporate admins will probably set IE 11 as default browser.
So developers of enterprise websites are stuck with IE 11 and its almost finished but a bit broken HTML5 support for years to come :(
If IE is there primarily to access the corporate intranet and other work-related sites, as usually seems to be the case in this kind of environment, then that stability is a feature, not a bug.
The last thing you need as a sysadmin for an organisation with thousands of members is someone who thinks they know better "upgrading" their browser to a new version that no longer works properly with critical business sites/apps, has unknown or at least untested-by-IT security issues that therefore may or may not require mitigation at corporate tooling level, and so on. This is particularly true if, as almost invariably seems to be the case, that individual won't be the person who takes the flak when something breaks, violates regulatory compliance, creates a security problem, etc.
I doubt there is a single organisation anywhere in the world that has IE locked down at corporate level, yet where any legitimate business purpose would be better served by having browser software updated every few weeks.