That isn’t remotely true. We do, fairly often, but it isn’t a situation of once you get rid of them they simply go away. It is a big industry with a lot of incentive for those folks to continue their illicit behavior so it is a constant struggle where sometimes we make huge steps forward and other times they are difficult to detect, prevent or eliminate.
I’m not entirely certain what your solution is, as I don’t think additional nodes would solve the issue, more likely exacerbate it. Feel free to post any suggestion you may have in the appropriate place, the Professions forum.
Additionally, if you encounter someone you suspect of botting, please use the right click report option. The more folks who use the reporting option the better those reports can aid in those investigations.