Most conflicts come down to practical matters like trade, land or other resources. As we are able to accomplish a higher standard of living in more and more parts of the world, we'll see less violence and less world conflict. Eventually, world peace may be possible for us to achieve.
Those who say the world has gotten more peaceful are burying their heads in the sand. We have many countries at war more than ever before and a saddening fact is that the different functions at war are supported by different countries escalating wars. Nations are spending billions of dollars in arming themselves with sophisticated weapons, which should not be the case if in deed the world is becoming more peaceful.
World peace is not in the cards. This is so because the nature of some people will always be to fight or try to gain more resources than others. I don't think any group of people or any country can be properly trained to stay peaceful all the time. If it were possible peace would already be commonplace.
World peace is a pipe dream. Humans will never be able to be completely peaceful with each other because we are a flawed species. However, we are becoming more and more peaceful as time goes on. This seems incorrect to most people, because violent events are more widely publicized with TV and internet news, along with social media.