The only reason RMTs keep "winning" is because people keep visiting their sites and getting keyloggers on their computers, thus giving them more CCs/accounts to use for more spamming and gold to sell.
If a company would actually educate their playerbase on what RMTers actually are and do, then the numbers would drop drastically.
You could probably mitigate more RMT bots coming into existence by forcing your clientele to watch a 5 minute video on what RMTers are and how to stop them than by mass banning bots that get replaced in 5 minutes because people are too stupid to stop visiting these sites in the first place.
Just looking at this thread is more than enough evidence that people really don't grasp how RMTers actually work.