Two words: job security. (Also: lots of folks really don't enjoy learning new stuff. Or new ways of working. No, they really don't. Even if the new techniques

Two words: job security. (Also: lots of folks really don't enjoy learning new stuff. Or new ways of working. No, they really don't. Even if the new techniques are vastly better and more efficient. Put this down to a human cognitive bias favouring the tried-and-trusted over new-and-untested. There's a lot to be said for that when you're a neolithic hunter-gatherer or an iron-age peasant -- if you try something new and it fails, you maybe get to watch your family starve next spring -- but it's a bit less useful as a rule of thumb in the data centre.)