Let me put this thought out there. What if that day comes. We learned everything about the origin of the universe, enough to proof that the scientists were right on their theories. But what if, at the same time, included in such knowledge, we get information that makes us realize that what we just acquired is only, at the most conservative level, 0.00000001% of everything else besides that there is to know? Would God be dead then? Will religion be forgotten then?
To think that answering the question of the origin of the universe is the end of our quest for knowledge, puts us pretty much in the same boat as the believers. Now I am not saying here that you are implying that we are 10 years away from answering every question humans have. If I understand correctly, you are saying that we would be at a point where it will be pretty hard to believe in a creator. But then, who lit the match at the big bang?
There is always going to be another question that, while the answer isn't around, God will come as a placeholder.
Or may be we are just one of many cycles of existence that have occurred and will continue to. Have you ever read "The last question" and "The last answer"?