Demise of a Friendship

We all know that death is inevitable. It is the purest form of truth there is, but does friendship die? The answer is an obvious yes. As early as kindergarten, you realize the importance of friendship and for as long as you live, you continue making friends, yet there are friendships that die. Even the closest ones. In some case, you simply move and lose touch, in others you outgrow your friends, some fall apart and some just die a natural death. I am intrigued by this a lot and would like a perspective from you on what your opinion is about this subject.