If you have thousands of machines running an OS that works perfectly well for your purposes, then you only upgrade when support lapses, which is 2014 in this case.
I'm not buying it. This is the reason always given, and in real life I've not come across this as the actual reason. 99% of the time it is lack of staff and will not lack of "We don't know how to make the adjustments to make it work."
I've also seen universities with faculty and staff still using IE7 not because of infrastructure requirements, but just because nobody had come around to upgrade because they hadn't bitched loudly enough.
I've also seen universities with faculty and staff still using IE7 not because of infrastructure requirements, but just because nobody had come around to upgrade because they hadn't bitched loudly enough.