Good idea but the truth is Dish is making a $$#&~load of money retransmitting locals so they won't.
It's hard to say but I'm sure in some markets they make a nice margin, others they may lose a little, and some they may break even. What they could do, and be transparent as possible about it, is something like this (using my market as the example and just made up numbers!):
AT120 = $64.99
ABC ($1.59 + 25%) = $1.99
CBS ($2.05 + 25%) = $2.56
FOX ($1.64 + 25%) = $2.05
NBC ($1.75 + 25%) = $2.19
Problem is, there's no consistent pricing and that alone could be a deal-breaker for Dish to implement it. Customers or potential customers could walk away because "their locals are too high", hence why Dish currently, and has always, charged the same for all markets.
The 25% adder, you ask ? Dish, without question, incurs costs for transmitting the local channels and should be compensated for that. Use the argument, "but the locals are broadcast for free" ? Fine, put up an antenna. Queue the "but I don't want to spend money buying an antenna and paying someone to install it", "I can't pick up locals where I am", "I'm not allowed to put up an antenna" excuses.... Dish is providing a service by getting the local channels to you - so pay for it.