Paul is clearly addressing believers. Some of these "believers" have been chastened so severely that they have died.
He is addressing people who were members of the Corinthian Church. Paul does not know who is truly born again and who isn't. So those who died didn't have to be born again, just members of the Church.
I figured you'd throw in "the flesh and the devil." They are part of this worldly experience. You can't be overcome by the flesh or the devil and still go on to overcome the world.
Jesus says 3 times in Matthew that "he who endures to the end shall be saved." It also says in Revelation to the 7 Churches that "he or him who overcomes" will get to eat from the tree of line and so forth.
Actually what you are saying sounds like the Hyper Calvinist understanding of "once saved always saved" that you can get saved, then live like the devil, and still make it to heaven.
Here is the more orthodox understanding called Perseverance of the Saints. Compare #1 with #3
Of the Perseverance of the Saints
1. They, whom God hath accepted in his Beloved, effectually called, and sanctified by his Spirit, can neither totally nor finally fall away from the state of grace,
but shall certainly persevere therein to the end, and be eternally saved.
2. This perseverance of the saints depends not upon their own free will, but upon the immutability of the decree of election, flowing from the free and unchangeable love of God the Father; upon the efficacy of the merit and intercession of Jesus Christ, the abiding of the Spirit, and of the seed of God within them, and the nature of the covenant of grace: from all which ariseth also the certainty and infallibility thereof.
3. Nevertheless, they may, through the temptations of Satan and of the world, the prevalency of corruption remaining in them, and the neglect of the means of their preservation, fall into grievous sins; and, for a time, continue therein: whereby they incur God’s displeasure, and grieve his Holy Spirit,
come to be deprived of some measure of their graces and comforts, have their hearts hardened, and their consciences wounded; hurt and scandalize others, and bring temporal judgments upon themselves.
But somewhere, God turns them around, not kill them to take them to Heaven.
Matthew 19:26 But Jesus looked at them and said to them, "With men this is impossible, but
with God all things are possible."