To answer this, God is a just God. If the penalty of sin is death, then surely someone had to die to pay the price. God could have just swept all mankind's sins under the rag, and acted like nothing ever happened. But such would not be considered integrity or righteousness on God's part.
Also if by one man (Adam), sin came into the world, and all men were considered sinners, then justly, by one man (Jesus Christ)'s death and resurrection, the price was fully paid, all men (mankind) can now freely claim the gift of righteousness.
>Why was it so late, so that people living earlier had no chance?
Well just like you stated, God is omnipotent, and not limited by time and space. It's never late or early in God's eyes. We would not explicitly say they had no chance, then or now, goes back to God being Just.