I say RMAH. They want to earn money. They could've balanced the game around trading without the abysmal drop rate. Even with a drop rate twice as good there would be much room left for trading. They could've also gone for a bigger character cast or a higher max level. More content. But they went for a drop rate which leaves you basically two choices, either quit the game out of frustration or go to the AH. And since grinding for gold takes a lot of time, well, it's quite easy to spend 5 or 10 dollars on a weapon. I mean, it's just 5 or 10 dollars, could save you so much time searching for yourself and...my god what a twisted logic. They programmed a flaw so deeply in their system, all out of greed. That may sound pathetic, I know, but I'm angry. Because I like the game, I want to play it, but I probably won't anymore because it feels like it's a waste of time.
Guess that explains why gems went off the market when the prices collapsed.