You failed to understand what this means. It pertains to the gift of the Holy Spirit. So in fact those saints were made perfect on the day of Pentecost. Hence we have this Scripture: To the general assembly and church of the firstborn, which are written in heaven, and to God the Judge of all, and to the spirits of just men made perfect... (Heb 12:23)...that they without us should not be made perfect.
So the OT saints have all been perfected, and are very much awake and alive. Why would anyone want them to be sleeping and imperfect after the resurrection of Christ?
At the same time, when the Resurrection/Rapture takes place, they will receive perfect glorified immortal bodies.