When someone redesigns, replaces or rewrites a technology that's been around forever, there are lots of reasons why people might not be enthusiastic. Some are less obvious than others.
There's plain inertia, of course: "The new way of doing things isn't the way I'm used to."
There's more active frustration: "I already learned how to do this once, why are you making me learn it all over again?"
And capability mismatch: "Arrgh, this specific thing I used to do a lot is difficult to do in the new system."
But perhaps less obvious, there's an erosion of trust. When a thing's _never_ been replaced, you learn it with reasonable expectation that the knowledge will serve you well all your life. But after it's been replaced _once_ by enthusiastic rewriters, you don't have that expectation any more. Who knows, in five years the next batch of enthusiasts might rewrite it again! So it doesn't feel like learning the new thing will pay back on the same time scale.
