Sure, some of it might be. But so are many other habits that we have. Marketing is a part of our culture know, and is inevitably influencing us, for better or worse. Charles Duhigg talks a bit about this in his "The Power of Habit".
If you're a professional and you have a tool that works and is central to your job, the manufacturer changing it feels more like a betrayal than it does catering to your need for novelty.
Office is a tool that works. People still complain about the Ribbon UI change, despite (possibly jusifiable) assurances that it really is a better UI.
