Okay, fine. Here's the definition from the dictionary.
innovate v. to make changes in something established, especially by introducing new methods, ideas or products.
Like it or not, Microsoft innovated with the GUI-based OS in the form of Windows by making it run on a wide array of hardware, i.e., a new method and product as per the dictionary definition. And if pushing your product in everyone's face is a "monopoly," (which it isn't--may want to grab for that dictionary you're so keen on referring others to) you're pretty much going to have to start accusing Apple of having a monopoly in regards to the iPhone and iPod which is silly, needless to say.
You could have said the exact same thing about the iPhone back when Apple introduced it. In fact, many did point out that there were existing products that were better at the time. How exactly does that matter?