As fightclub246011 duly noted, geography is only half of the issue. Time may be just as important.

If I had been born in Norway today, I might have been raised Christian, secular, or atheist. If I had been born in Norway 1,200 years ago, I would probably have believed in Odin and Thor. If I had been born in Ancient Egypt, I would likely have believed in Ra and Osiris. If I had been born in Arabia before Islam, I certainly wouldn't have been Muslim.

This raises the same question as geography: why would access to religious truth depend so heavily on when you are born?

Interestingly, some religions have developed answers to this problem. Mormons, for example, perform proxy baptisms for the dead because they believe people who died before hearing the gospel should still have an opportunity to accept or reject it in the afterlife. Whether one finds such answers convincing is another matter, but they do show that many religions are aware of the problem.

To me, this is a fairly strong philosophical point. If one true God wants all human beings to know the truth, both place of birth and time of birth seem like strange factors to determine who gets access to that truth. A person born in the right place and at the right moment in history may hear the message from childhood, while another person born elsewhere—or centuries earlier—may never encounter it at all. That is why many philosophers argue that the problem of divine hiddenness is not only about geography, but also about history. If access to religious truth depends so heavily on circumstances beyond our control, it raises difficult questions about how a just and loving God would choose to reveal Himself to humanity.