If everyone will eventually come to believe the Christian God exists anyway why not just show up now?

If there does come a day of Judgement where everyone comes to be judged by God everyone who didn't believe will most likely think "Looks like I was wrong". In fact, if any non believer in Christianity were to die right now wouldn't they instantly know their worldview was wrong depending on where they ended up? Everyone is going to end up believing the existence of the Christian God, but at that point it would seem to be too late. Whats the problem with being revealed in an unambiguous way while people are still alive?

Really this just has to do with why the Christian God isn't readily apparent to everyone who is alive/was alive. There doesn't seem to be a rational reason for not at least letting everyone know you exist first before they make a choice of whether to follow your commandments/worship you.