It will last until Blizzard changes how BGs work.

Right now you are REWARDED for quitting if you are going to lose anyway or if the game is going to be close. If you can lose in 10 minutes and get 1 mark or player for 30 minutes and get 1 mark, then many people will conclude the former is better. Now quitting goes against the nature of a lot of people (I never quit, for instance), but there are plenty that will give up if it gets them where they want to go faster.

To elaborate further, consider even a close game where both teams are playing very, very well. The losing side still only gets 1 mark, despite doing much, much better than a quitter team. The losing side spent a lot of time on that for no benefit. The losers there are punished harshly for even TRYING to win.

What Blizzard really needs to do is make bonus honor and marks scale depending how long the game lasts. If a game goes on for an hour then you should get twice as much bonus honor and marks than if it went for half an hour. That way people won't be punished for trying (and in fact they are rewarded since a longer game avoids as much queuing time).