The problem is, who really has money to afford these if they already have HID lighting?
They are not targetting indoor grower with this product, but commercial greenhouses who have thousands of HPS lamps. For these people, the price difference will easily be absorbed by the economy in electricity consumption and not having to change the bulbs every 1-2 years. And since they are only using the lamps as a supplement, they don't need a full spectrum, but instead target the most "efficient" wavelength (deep 660nm red with a little bit of "royal blue" 450nm) for photosynthesis.