We have the tools at hand to make an AI and have had programs that could fool people in a blind testing session (look up the program "
Eliza" for an interesting read on it) since the mid 1960s.
As far as "cheating," most of you need to understand that it's only cheating if the game disallows bots. After that, it's only sensibility. Is it really sensible to let bots run around unattended in a permadeath game, especially if it requires you to develop the character any at all? In Haven, it was (still is?) sport to kill bots on the spot. The need to attend to your bots to make sure they're not getting slaughtered left and right limits the number you can run.
As far as the game economy goes, I've not found a game one with a properly working economy that was ruined by bots. I've found that others willingness to use bots keeps prices down and frees my time up to do other more interesting tasks that the "farming" level industries. FYI, those that are having issues have a huge economic issue to begin with in the amount of in-game currency/items produced. Again you can blame the game designer for a ****** game.