If original sin brought suffering and death into the world, and Christ paid our debt, a theory to which I do not subscribe, then why do we still suffer and die?.
I think that until sin is totally done away with, suffering and death will always be a part of our life here on earth. And sin will not be done away with until Jesus comes again, judges the world, and everyone goes to their final reward.
Before man sinned, God ordained for us to live forever on this earth. But after man sinned, eternal life was taken away, because if each person still lived forever, sin would always be present and we would live forever with sin as a part of our lives. As Genesis says, “And the LORD God said, ‘Now that the man has become like one of us, knowing good and evil, he must not be allowed to stretch out his hand and take also from the tree of life and eat, and live forever.’”
This is why, even though Christ paid the price, we still die: because sin is still present on this earth, and we all still succumb. The weeds, the thorns, and the good seed must all live together until Christ comes and a separation is made. Then, sin will be done away with and death and suffering will be no more.
And we still suffer because Christ suffered. And we share in his sufferings because we are his servants. Suffering helps to perfect us. This is the reason St. Paul saw for his own sufferings: “Now I am rejoicing while suffering for you as I complete in my flesh whatever remains of the Messiah’s sufferings on behalf of his body, which is the church.” (Colossians 1:24)
I can understand how all the theories make sense. Perhaps they are all right in their own way. There were many aspects to Christ’s death, not just one. He is the fulfillment of all of the Old Testament offerings: and there was more than one. Each had a purpose, but Christ has accomplished it all.