High-end power cord manufacturers are in a bit of a pickle: if the power cords do everything that's claimed--that is, if they somehow make up for the "problems" in all of the wiring coming from your local power transformer to your wall socket--then why wouldn't a run of 2 feet, or 1 foot, or six inches (requiring only an el-cheapo extension cord) perform the same miracle, thus cutting down on the price of the super-expensive power cord material?
The answer is in the last phrase of the question.
The answer is in the last phrase of the question.