I'm not going to get into the "they should do xxxx to keep me as a customer" debate, because that's too much like the medieval arguments about how many Angels can dance on the head of a pin. :shock:
But, they defintely DO know what equipment you've had in the past. When I called about the "Dish 6000 remote fiasco" a month or so ago, they recommended that I try the remote for my 4000. I bought it at least six years ago and haven't used it for at least three years, but they knew that I had owned it in the past. It wouldn't take much programming to have some kind of flag that that particular equipment was purchased on a special deal.
I suspect that the 811 special may be a reaction to VOOM. If you look at General Motors website, you'll find discounts on everything except Corvette and Hummer. I suspect that the 921 is the same for E*.
Having said all that, I'd love to get a discount on a 921.