True as that is, Blizzard could correct the problem by reducing the server capacities by a small degree and offer free transfers to medium and low realms, which in theory would become high populated again. It’s up to the players, and Blizzard has deemed it futile to go in that direction because people are willing to sit through queues to play on the largest servers possible.
EDIT:
If the players truly wanted Vanilla server capacities, or slightly larger capacities (say by 1000 or so additional players they would have tried their best to have organized a something similar boycott on the forums and spread out on the servers available after launch to have Blizzard realize the players truly want the game more in line with Vanilla server capacity.