Board Thread:Warhammer 40k General Discussion/@comment-24037808-20140109121720/@comment-94.11.220.176-20140307193413

The reason that some human settlements, planets or even star systems turn to chaos is that they are disillusioned with the current state of the imperium (fractitious governments etc). If the Emperor were ever to rise from the golden throne (as unlikely as it is) he would likely be able to re-unify the Imperium and lead it in a new direction. And as other people have mentioned, the Tau lack the manpower, firepower and transport capabilities to launch their own version of the Great Crusade to bring all of humanity under the "Greater Good".