This.
The end.
If Blizzard's economists estimates that at $2 for their product they would sell it to 50 customers, while at $3 they would sell it to 40 customers, Blizzard executives will decide to sell it for $3 because their estimates tells them they will make $120 at that price, compared to only $100 dollars at $2.
It's not about content versus price. It's about how much are people willing to pay, period. Given how they sold over 10 million copies of Warlords of Draenor right now they are thinking that yes... people will pay that price.
Blizzard is a business owned by shareholders who expects them to make the best profit possible. Working as intended. Vote with your wallet.