Orlais managed to beat the elves of the Dales because the Divine called an Exalted March and enlisted neighbouring countries to help. Without this intervention the elves might well have taken Val Royeaux. Also the elves possibly over reached themselves because I read that whilst they were marching on Val Royeaux, the opposition attacked and burnt Halamshiral. Presumably they then started to advance on the elves' rear. Also at some point the Dalish leadership (their nobles) decided to cut and run and left the rest to be killed, kill themselves or be captured. Hence the reason why those elves who became the Dalish nomads (who fly the banners of Dalish nobility) had sufficient strength to be able to cross the Frostbacks and destroy the first barbarian clan they encountered. Hardly the actions of a battered and bloodied army fleeing for their lives, where the more appropriate action would be to slip away quietly, not drawing attention to themselves.
I tend to feel that the ancestors of the current city elves were betrayed twice during the War of the Dales; by the humans in having their homeland taken away from them and by their own leadership in abandoning them to their fate. It was a combination of the two that allowed the humans to crush the elves and reduce the majority of them to little better than slaves in terms of the way they are treated.
Where people do follow the Chant and worship the Maker, the Chantry ought to ensure that they are treated fairly in accordance with the instructions of the Maker contained in the Chant. In the case of the majority of peasants, but the elves in particular, the Chantry has failed to do its duty in this respect.