What are three possible long-term consequences of two species occupying the same niche?

On the basis of the competitive exclusion principle, the two species cannot thrive in a similar niche for a prolonged time period and coexist stably. This is due to the fact that the species with identical niches seem to exhibit similar requirements, thus, the competition of similar resources.  

As a consequence, of the two species one can occupy and adapt the same niche, can get eliminated and die, or may drift to a less competitive region. One of the species may end up in becoming more efficacious than the other. And on certain occasions, when the struggle is not that tough then one of the species may get develop to possess somewhat distinct niche.