So we’re all guilty because we didn’t invent time machines to go back to the year 1000 and preach the Gospel to the Aztecs. I suppose that since we got our lazy backsides to sub-saharan Africa around the 1700’s or so and started preaching the Good Word to the natives meant that magically their ancestors also are saved.
Every person is responsible for themself and their response to how God reveals himself to them. Even those who never heard of Jesus. Paul explains it in Romans 21, starting in verse 19.
They know the truth about God because he has made it obvious to them. For ever since the world was created, people have seen the earth and the sky. Through everything God made, they can clearly see his invisible qualities – his eternal power and divine nature. So they have no excuse for not knowing God.
Those of us that get to know Jesus get the full gospel message. We're very fortunate to have his and his disciples' words as a guide for life. Our acceptance/rejection of Jesus and his message will determine our eternity.
Those that never heard of Jesus won't be judged by God like we are. But they do have general revelation of God from nature, their conscience, innate reasoning capability, and awareness of morality. How they respond to God based on that general revelation will determine their eternity.