If you lived a stress-free life all the time, that would be awesome. However, you would not think of it as being peaceful. You wouldn't even think of it at all. It would simply be the way things are. Without any hardships to compare things to, living stress-free is simply living another day.
Peace comes out of chaos. Or more accurately, the idea of something being peaceful can only exist by knowing what chaos is like and not experiencing it.
This ends up being a sort of twisted facet of humanity: the harder a life somebody has, the more deeply they appreciate simply not being in the muck and mire.