I think that the comparison of satellite to cable has to be made on a case by case local basis. We have had Dish (non-HD) for about 5 years now. Our broadband cable provider also has cable TV so I priced it again recently, as I do from time to time, and it was actually slightly more expensive than satellite with the configuration we have.
You would think since I get broadband from them, the cable provider could discount the cable enuf to make it attractive to add on, but they won’t, so we will stick with satellite. Plus in our area, SD satellite is widely accepted to have a slightly better picture than the local cable provider.
I’m sure it is a case by case decision. And as with you, Comcast isn’t known for their discounting; at least over a long-haul relationship. They may give initial discounts to draw business, but those soon drop.