It was really a series of coincidences and twists of fate that led to the seven being on the Enterprise. Instead of time "making things right," it may make one think of how little control we may really have over our fate.
For example, things would've turned out very differently if McCoy had not been assigned to the Enterprise, and had taken Kirk aboard, say, the Farragut.
Considering the theories that say that there are infinite universes that unfold in infinite ways, there may be many where Kirk, Spock, and McCoy never met or were never even born. Of course, those universes wouldn't be as much fun as the others.