You ask a good question: Why dont we see the miracles Christ said would happen? I think it is because we do not truly believe him, that they will happen. Jesus tells us, in Matt 17:20, "If you have faith as a grain of mustard seed you shall say unto this mountain, remove hence to yonder place and it shall be removed, and nothing shall be impossible unto you." So if we believe that, we will act on it and see the powerful results. There are some who do believe, but they are few. I attended (and had the privilege to participate in) a church, in Cincinnati, OH, in which such miracles took place. Even so, when they did, many skeptics arose who said they were faked and refused to believe them. So some will refuse to believe, thought miracles take place right in front of them. But for those who do not, these miracles attest to the present power of God, still active and alive in the world today.