War is hugely profitable. It creates so much money because it's so easy to spend money very fast. There are huge fortunes to be made. So there is always an encouragement to promote war and keep it going, to make sure that we identify people who are 'others' whom we can legitimately make war upon.
Because a lot of people are hurting economically and being shafted by the very wealthy, it's been possible here in the United States of America to organize them and persuade them that to elect a nincompoop like Donald Trump is actually in their best interest. When clearly it isn't.