Gentlemen,
I obviously come into this argument with a bias toward the cable viewpoint, but let me suggest a slightly different way of looking at the situation: The cable companies will adopt HD, and they'll do it because it's important to their business.
The majority of cable operations (not all, thank you) have been dragging their feet, not because of the cost of the boxes, but because of the scarcity of supply. They simply did not want to endure the pain of putting customers on waiting lists, eat the truck roll expense of replacing boxes with a 25% failure rate, and listen to the complaints of customers over both. Some, non-HFC (hybrid fiber-coax) systems, just can't do it.
Some, like us, felt it was important enough to people like you to go ahead and launch, and to work through the logistical hurdles. We did it because we felt it was important to our customers, and thus, important to the future of our business.
Others will get on board because they either realize, or will shortly realize, that HD is important to their business.