Yes, man is born lost and thus in his current sinful state on the road to be condemned, but no one is fully condemned until they die and face judgement, as long as they still have an opportunity to believe the gospel their condemnation is NOT sure.
Now, regarding those who have not heard, I think this particular commentary states it very well:
In Romans 1 Paul teaches "that God has revealed Himself in creation ( Romans 1:18-20 ) and in human conscience ( Romans 2:12-16 ). Paul said that each individual will be judged according to his response to these two revelations of God. To those who respond positively, God gives more knowledge—as He did to the Ethiopian eunuch and the Roman centurion, Cornelius (see Acts 8,10 ). Those who are lost will be judged according to their response to the spiritual light they have received ( Hebrews 4:12-13 )....In the final analysis, we must leave this matter in God’s keeping. He is both just and loving. We can be assured that the Judge of all the earth will do right ( Genesis 18:25 )."
So, why was a man condemned in the OT? Was it because of his sins?
Regarding those in the past Paul said, "God was reconciling the world to Himself, not counting their trespasses against them, and He has committed the message of reconciliation to us."
Jesus said, "God presented Him as a propitiation through faith in His blood, to demonstrate His righteousness, because in His restraint God passed over the sins previously committed."
Clearly God was willing to "pass over the sins previously committed" and thus it was unbelief that condemned the man. The same is true today.
Think about it this way. What is one difference between those who will be in heaven and those who will be in hell? Is it the sin? No, all are sinners, some in heaven will be even "worse" on a scale. The difference is faith. Those in hell are there ultimately because of their unbelief, period.
"Without faith it is impossible to please God."