I liken Mat's proclaimation similar to Rand's declaration of Aiel's history in the Golden Bowl. Maybe two thirds of Seanchan would convert to Mat's point of view, and one third overcome by bleakness, either create their own kingdom with collared damane, or killing channelers indiscrimately.

Anything that earth scattering would produce those kind of results. It could be argued that this kind of collateral damage is unavoidable, and already occured in every other culture, including the WC. So maybe it is due for Seanchan.