That's a very good point and I can see that scenario playing out. I'd like to think that your scenario would not apply in all cases or to everyone. I believe there are non-believers, like me, that would've accepted Lazarus coming back from the dead.God is not a genie in a bottle who will pop out to grant wishes to offer evidence of His existence. God has already provided plenty of evidence. If people refuse to accept the clear evidence God has provided, why would they ask for more? Jesus called Lazarus from the dead after being buried four days. Numerous people saw Him do that, but not all of them believed He was the Christ. Many left to tell the religious leaders what Jesus had done. The truth is, the religious leaders plotted to kill Lazarus to silence him. So again, people who do not want to believe, never will regardless of the evidence presented.
Here's another scenario that I see being relevant today (how much, i don't know). Let's say we have people today that have probably witnessed little to no encounters of Jesus or anything supernatural. They genuinely want to believe but want clear-cut solid evidence as opposed to being offered vague evidence that can mean different things, assuming it means anything at all (there are natural explanations that can account for the information or at most it's too vague or weak to draw any conclusions either way). I think we need to give these types a chance. These types can be atheist or agnostic.