Um... because the Internet is not just IPv6? What grounds would they have for that? If IPv6 were a selling point, then you can bet your arse that it would be appearing in the adverts. Hell, they'll make up technical stuff just to sell something, pro-vitamins and probiotics and synergistic omega 3 complex oil hydrating compound...
We've already got BT's Superhubs, BT Infinity and Virgin's DOCSIS3 advertisements.
They'll wake up when they decide to wake up, and when they decide they can use it to distinguish their product from every other bugger's product.