Wars pointless why do people fight like that?

i mean no matter what reason you have for war in end everyone ends up screwed why doesn`t anyone look at the consequnces because im pretty sure in a few years we might go into a war for oil but after that war the earth would just be one big irradated desert i mean so what if some terrorist country nukes im pretty sure there are other measures the couldve been tooken to prevent them from getting it in the first place