Things can easily go out of control in a war if the political career of the person who decides when the war ends depends on the war. If that person is told he will be finished after the war, he may very well think to himself this war will not going to end anytime soon.
Netanyahu’s future is clearly tied to the war. He knows he will have no chance of survival when the war is over. This is the worst situation when a long war is actually beneficial for the one who decides when it ends. He calculates that most probably long-term war will escalate throughout the region and that is exactly what he needs.