I kind agree with you in the sense that this should be the understanding in lay life. However, it is no accident that Buddhism is still at its core a religion of monastic renunciates. This actually supports your connection to attachment theory. In some cases people’s ability to attach has been so damaged (from trauma) that monasticsm seems the only way of finding some degree of stability, wholeness and meaning, especially when one feels unfit to be in a relationship or have a baby (which would only perpetuate those painful attachment issues to the next generation). This is why Buddhists say they take “refuge” in the three treasures. It may literally be the only place for such poor souls to go.