Many species have died out for many reasons, one day we will not exist as a species like the one we are today. As far as a balanced nature, many times the total worlds population has been increased and decreased, in number, in total mass, in levels of intelligence, once upon a time there was zero life on earth, so balance is our own perception of what things should be based upon what we have experianced and our knowledge.
One day, if we do not leave the planet, all life here will die out, and even if we spread out through the universe, there is still the possibility that eventually all trace of us might disapear. These things have probably happened in other places in this unlimited universe.
The eagle and its prey is a nice snapshot.