That's the question posed by this Mercury News article. The actual title references HDTV's being available since 1998, which I don't think is really fair because they haven't been priced within reach of the major audience until the last two or three years. While confusion has definitely slowed adoption, I can't even count the number of times I've heard people say conflicting and erroneous facts regarding HDTV, the biggest barrier is price and it is continuing to come down.
As the price hurdle falls, yes, consumer education will probably be one of the largest difficulties but hopefully people can find sites like this one, or any of the resources manufacturers and content providers are creating. As more people see high definition TV's in their friends homes and programming increases, they'll want it for themselves and be able to get it. Of course, then we have to make sure they are actually watching high definition TV, but one step at a time.