War is quite useful sometimes - it prompted the end of Saddam Hussein's horrific regime, and, in reference to the original post, prompted the end of Hitler's even more horrific Third Reich. The only times when modern wars cause more harm than good is when those on the other side are religious extremists who realize that the war may kill them and consequently threaten the strict religious principles they stand for. Who will carry on their fundamentalism when they've been killed? The easiest answer is their children, and so they continue to distill in them an immense hatred for the forces that threaten to destroy their religion. That is why ISIS is a problem for us today - they seek revenge for the 2003 invasion. I can almost go so far as saying that war isn't the problem - religious fundamentalism is.
None of the wars taking place right now is for money. Most of the fighting happening today is happening in order to allow Western women to keep walking around without a hijab if they so desire, and not get acid in their faces if caught without it.Wars are exclusively made for profit these days. Probably a few hundred years ago, they had founded reasons to occur, but now... the continuous blood shedding is exclusively happening because money is taking our mind away.