I did not have the time to reply to this the other day but I saw it today and will point out some major flaws in your logic.
You are missing the logical point that the RMT obtain the gil from the wealthy thru selling them goods. In order for the wealthy in any MMO to get wealthier they must consume goods as well. In this case, they are buying "Goods" which were botted for by RMTs. If you remove the RMT, the player population now can get the gil from the wealthy players without having to pay gil-hostage/real money to get gil thru RMTs.
The RMTs are not Robin Hoods.
In order for the wealthy to get wealthier they will consume goods and they will do so as long as they have a profit margin. So even if RMTs are removed they will buy from players if even if the raw materials are slightly higher in price as long as a profit margin exists. RMTs do not redistribute the gil. They are taking the gil that should be redistributed and hold it hostage.
The idea that RMT's help redistribute the wealthy player's gil is false when in fact, that is the same gil that would go to players if RMT's did not take it hostage.
Please look in to the logic of your idea.