"Charge because you can fees" seems to be a popular term on here. Are you saying this is just a Dish thing or are you saying that every provider that charges for HD, extra receivers and DVR is doing the same thing?
It is not really charge what you can, but what they think they need to maximize revenue and still remain competitive. The relative cost for a receiver to Dish has come down over the years, yet the fee has gone up. Your $7/month is not really covering the cost of the receiver (you pay it even if you bought it up front), but as a fee mechanism Dish uses to bring in more money. This is not to be construed as trying to screw customers out of cash but a way to get more revenue for a logical reason that the consumer can understand.
The business model is that there is a base package fee that is advertised and then you put on a bunch of fees below the line. In the past Dish tried to resist, but now they have joined the rest of the industry.
It is like Southwest Airlines. Currently they do not have a baggage fee. Does this mean that they do not have to pay for extra jet fuel to carry bags? No, but they think it is a better way to advertise being no fees on luggage, or ticket changes. Why do other airlines charge $25 when studies have show it is really only around $2 extra cost to the airline for a checked bag? Well it is a profit center that helps the airline to break even.
Make no mistake every fee that Dish and all the other providers have are completely decided by them, they could waive any of them if they decided they would get more customers and profit without them. Why does Dish now say they have a $10 HD fee? Well perhaps they never intend on charging it, but it looks good to say you get another $10 off for 2 years when they make their ad up - and there is more! save $10/month off the price for fee HD for 2 years!
I am sure Dish (and all the others) carefully study the impact of every fee. I am sure they have focus groups to see if they can make it sound reasonable and logical (i.e. you got another box so paying $7-$17/month is reasonable). They also then are able to use that money to lower the package price, or perhaps give more incentives to new customers.
Dish's least profitable customer is probably someone with just one 211 with EHD. No extra fees, just the base package price. But, they elected to set the system up that way. I am sure they are still making money on that customer, just not as much as others.