But why would fate make sure Kirk and his TOS season 2+ crew united, and not the "proper" crew of Pike or even Kirk's "Where No Man..." crew? And why would fate allow Amanda and planet Vulcan to die?
Besides, we're working with incomplete information, comparing 2258 in one timeline with 2365-66 in another. By the time this movie trilogy is over, the crew may not be intact. They may have united early just for members to die or move on prior to 2265-66. McCoy may die and Dr. Dehner (Alice Eve, just speculating) may take his place.
Then again, after having read the recent (and utterly fantastic) Voyager novel The Eternal Tide
...maybe the universe is ensuring it's own survival by uniting Kirk's crew at all costs. Maybe it's to stop the space amoeba in a few years? The multiverse summons it's antibodies!