Incidentally, Memory Alpha claims Surak's demise was part of the final battle where the raptor folks supposedly lost. But the actual phrasing suggests that Surak died before that battle. Days before? Years before? Decades before? Centuries before? Everything is possible.
There's a pseudo-religious aspect of the way Surak's teachings have been presented that lead me to believe that, at least dramatically speaking, it makes more sense for Surak to die before his followers win. By the time they win, the teachings have been corrupted (I personally don't believe Surak would have even condoned fighting those who opposed to).
Diane Duane's novels suggest Surak died in an attempt to mediate peace, far away from home and thus supposedly far away from Mount Seleya. The flashbacks from ENT "The Awakening" don't necessarily contradict this claim, as Surak is shown dying of radiation poisoning. He may have been poisoned during his diplomatic visit, only to die at return to his ancestral lands.
I like this idea a lot. It fits with the nature of Surak (both when originally seen and in Enterprise). He's a man that abhors all violence and I think, in Enterprise, he was appalled at the way his Awakening had been used for more bloodshed. Although, in the end, I do think that those who opposed his teachings chose exile and the violence of Vulcan did come to an end (those who remained did choose a more pacifistic, logical society than that which had existed before him).
Right now, the writers seem to try to mostly imply that the Romulans left because of Surak and his logic movement, but don't outright say it.