Yep...ever heard of Coutour? They've arguably got a better product because of their form factor that's less obnoxious to wear. But almost no one has heard of them whereas GoPro, as you point out, is synonymous with this type of video.

But there's another facet to this kind of marketing. Try contrasting videos like this that GoPro puts out for promotional purposes with the kinds of videos that the average person creates with a GoPro. These are fun to watch and full of unique views of cool stuff. The ones that average people create are, for the most part, boring. Yet their market is 99% people who make the boring kind of videos. If their marketing showed the kinds of videos that most people would be creating, no one would buy them. By showing videos like this, they get people inspired enough to think that they can shoot something cool.