It is possible for the human brain to compartmentalize these two ideas:
1. The universe works by a set of laws reliably. There are chance events, but no supernatural effects occur. Science assumes this and works very well on that assumption.
2. God invented the laws, but is still involved in human affairs.
Religious scientists do this compartmentalizing. The problem is that if God is currently too active then science can't work. How active does God have to be before science can't work well enough? I don't know, but assuming he doesn't do anything seems to work just fine, so why assume he's there doing little to nothing? Because it makes you feel good? So does Santa.
Religious people living in the modern world compartmentalize also. They live their lives as if God doesn't exist, doing almost everything as if it depended on them alone. Occasionally during the day or week they rely on God, especially when they do everything they think they can, and hope He'll do the rest.
Only very strange people pray every time they get in their vehicle. Some religious people pray before they go on long trips.
Only very strange people pray every time they look for something. Some religious people pray after they've looked everywhere they can think of and can't find an important item.
There are many more examples.
One could argue that we are all over 99% agnostic because over 99% of what we do ignores God. Less than 1% of what a religious person does specifically relies on God's help.
You cannot tell whether a person is agnostic or a believer based on most of the actions they do during the day. Watch drivers and try to predict their level of faith. You could use their bumper stickers, listen to their curses, and such things to help, but you would only be making intelligent guesses. Agnostics drive about the same as believers do.
If God really existed and blessed the righteous based on their faith, you would see a lot more religious activities all day. People would be praying before practically everything they did. Statistical studies would show the positive effects of prayer, etc.
"God, should I do this or do that?" would be prayed over and over again during the day. Those people who prayed would have a significant advantage over those who didn't. Atheism would disappear.
Atheism can exist because there is no significant difference between the success rate of those who almost entirely rely on themselves, those around them, circumstances, and luck, but occasionally on God, and those who rely entirely on their own abilities, those around them, circumstances, and luck. On the other hand, those strange people that try to rely entirely on God either quickly change to having less reliance on God or die from God's inaction.
I claim that if God really existed doing the things people claim he does then atheism wouldn't exist except as a mental disorder. Atheists would not be successful in life. I consider the success of atheists as evidence against the existence of God.