The "natural man" -- the unsaved sinner -- is perfectly capable of comprehending the plain Gospel. If it were not so, then Christ would not have said this: And he said unto them, Go ye into all the world, and preach the Gospel to every creature. He that believeth and is baptized shall be saved; but he that believeth not shall be damned. (Mark 16:15,16)
That command pre-supposes that all men can understand the plain Gospel -- that Christ died for their sins and rose again for their justification. Those men gathered in Jerusalem on the day of Pentecost were all natural men -- all sinners in need of the Savior.
But Peter preached the Gospel to them and told them that they would receive the Holy Ghost only after they repented and believed on the Lord Jesus Christ. And it is only AFTER that that men have the indwelling Holy Spirit to understand all things spiritual.
Therefore you are misunderstanding and misapplying what is said in 1 Corinthians 2 about the natural man and the spiritual man. You have refused to give up your false belief in the face of probably hundreds of rebuttals.
Colossians 1:23, says that the gospel WAS (past tense) preached to every creature which is under heaven.
The natural man cannot discern the things of the Spirit, 1 Cor 2:14. Believing in the gospel, which is about the things of the Spirit, eliminates the natural man from believing the gospel.
Saved, in Greek, means "delivered". Baptism is an answer to a good conscience, 1 Pet 3:21. which saves (delivers) the spiritual man from the guilt of a bad conscience, and it does not deliver him eternally. He has already been delivered (Saved) eternally.
Jesus instructed his Apostles to go and preach to "the lost sheep, (who are regenerated babes in Christ) of the house of Jacob"