The problem is, there is no upper limit on "enough". Wars have been started on grounds of vital resources like food, water, etc. it's not common nowadays, as technology helped us to produce food more efficiently, and it's enough for the current population of the planet. Maybe it will not be enough for 15 billion people, which is not happening in the near future.

But then there are wars started on grouds of religion (ISIS), or territorial agression for the future generation (WWII), and none of these has to do with current resource limitations. These are based on ideologies that are made up and controlled by few and distributed via media.

Technology has made it possible to spread these kinds of ideologies more efficient than ever. It's everywhere, in news, facebook, even in Hollywood. And it is slowly transforming people to accept a greater level of violence.

You mean like WW2?