Originally Posted by
SaibotLiu
I'm pretty sure the reason most MMOs discourage this is so they can remain consistent with the standard rule that you don't own your character or any of the virtual items or currency you've accumulated on your account. If the EULA doesn't prevent you from selling those things for monetary gain then they would have a much more difficult time furthering the narrative that you don't own them in the first place. And if a player can establish that they actually own things on their account, it potentially creates a lot more problems for a developer than just unauthorized RMT.
I think players have this perception that it's about the company losing money or it's because of the fairness aspect, that's probably a much lesser concern in most cases.