That might be true when you increase the number of players while holding number of regions constant, but what has been done in practice is decreasing number of regions while holding player numbers constant. I don't think the latter case can logically lead to more realms.
It COULD, since again forcing density has the propensity to force internal conflict which leads to splits. But as with all things it makes assumptions, like characters being different enough to create the conflict, characters with the opportunity and power to do something actually being involved etc. However Chénier was making general statements about density, not necessarily stating that actions like the glacier to force higher density would result in more realms.
