DOT Bans Upgrades. Upgrades for upgrades sake may not be good, but getting to the point where you can't upgrade anything because a critical app has not been upgraded and no longer can be isn't so good either.
I think the upgrade game is a tricky one. As is the question as to whether or not to carry maintenance/software assurance on software. It is a lot like insurance. If you have an accident you are probably happy that you have insurance, if you don't you are kind of sad that you just threw away good money.
If the number of upgrades in a maintenance window are such that upgrading would have been cheaper, you just made the wrong choice. If there were enough upgrades then maybe you didn't. You also have to play the game as to whether or not you can do an upgrade or if the licensing is such that you would have to purchase full licenses all over again.
The interdependencies between one application in an environment and another can make the game harder to play. In the government arena having IT staff (and staff in general) get smaller and smaller means that research and development in regards to upgrades is usually less and less. You are down to a staff that is tasked with keeping the day to day going on what it has to work with and does not have time to work with the latest and greatest, thus finding themselves in a sink or swim scenario when upgrade time comes.
Not to say that one cannot make a financial reason for swapping things out on the basis of the cost of the software itself, but it seems that training and staff experience are not weighed into the scenario.
If you simply add other environments, then you add additional variables into the support mix. I am not saying buy only Microsoft and only stay with Microsoft, I am just saying look at your options and implement them intelligently or you won't be gaining anything.
Of course, as a CIO, not spending money reflects well on you to upper management, but if you are the CIO that inherits a shop that hasn't done upgrades for an extended period of time upper management won't be so happy when you bring the bill to bring things to current levels.
I have a cold and am simply rambling at this point. Feel free to throw in your own thoughts.