This attack has costed more than you would ever compensate for the attacker so its not that great business plan..
Yes, DDoS attacks are super expensive. Not just for us defending, but for them initiating them. That's why we highly suspect that they have to have another source of income, e.g. selling game bots. And these kind of attacks should provoke us to lessen the bans for bots. But we won't.
I wish, we could use all these resources to actually improve the game and implement some player wishes. There are so many great ones just waiting to be worked on. Especially now would have been a great time since the BBash worlds were so stable and we didn't phase those lagging issues we had on other specials before.
At least, the newest measures seem to really work quickly in defending against these attacks.