If you really think about it, design can definitely change the world.
The degree, the direction and the ethical value of that change might vary, so perhaps the accomplishment of what that phrase “change the world” usually means (as in “make a difference”) might not happen almost all the time, but change as the abstract concept of “making something different” is inherently what design does, so just by existing design is by definition changing the world.
I’m even compelled to argue that design is by definition “the process of changing the world”. So when design happens, there’s a change in the world.
If you’re not confortable with these arguments, perhaps it is because you’re thinking of a much more defined interpretation of “changing the world”. That, as with many design problems, is due to a poor definition of the problem to be solved.
Perhaps we, instead of uttering short, emphatic, compelling phrases like “design can change the world” should dedicate more time to really defining what we mean with it, as in “can interaction and visual design make a large part of the world population live a better life?”. The answer to such question being a rotund “Not at all. It requires much more than those disciplines to create a solution that can achieve such goal”.
(Inspired by A New Yorker walks into a San Francisco start up…)