Why arent they doing anything?
Looking from an Economics point of view, when i talked to an economist, about how WOW manages the incoming and outcoming of $$ like in real world... dungeons, items and professions are how the money comes into the game...
and mounts, pets and repairs and AH cuts, are the main ways of taking the money back.. so the prices of the products stay fair, and the game doesnt become like many other games, like diablo 2, where the money was useless (the real trade money were SOJ's = stone of jordan rings"...
So when ppl start botting big time, specially PETS, which cost huge amount of money, and are rare to find (if you dont stay there grinding for like 15 hours straight..like a regular sane person would probably never do) they actually unbalance the money market and its flow...
they dont ban everyone couse, like was said before, cuz they dont want to.. couse they would loose the biggest market for them (chinese duds)... they made an agreement with Pyrox, but it think was more a way of showing to regular players, that they are doing something about it..
All I'm saying was an analysis from an economist friend of mine, my field is medicine, so Wow, only for some PvP... and chillaxing... =P
I'm not american, so sorry for any misspeling of if i was not very clear of what i1ve tried to say...