The best survival strategy is to team up with other young males and form a bachelor herd. It's safer, but still lonely. Hence a bachelor springbok will repeatedly challenge the dominant male, risking injury and death.
It's not easy being the dominant male, either. Dominant male springbok are so busy mating with females, stopping members of their harem from wandering off, and fending off challengers that they have no time to eat. After a short period of dominance, they are so weakened by their efforts that they, too, become easy pickings for predators.