Imagine this test:
A higher power grants you everlasting life. The catch is you are required to perform a simple task over and over for eternity. The task is to locate a coin on the table in front of you and recognize that it is "heads" up...then pick up the coin with your right hand, transfer it to your left hand, then transfer it to your right hand, then put it back on the table heads up. You are not allowed to make a mistake or to drop the coin.
How many years do you think you can do this simple task without making a mistake?
If you answered infinity, you are an idiot.
This little mental exercise should be all the proof you need to conclude that everyone will have a negligent discharge eventually if they live long enough.
Of course you'd make a mistake. Your life would be so miserable, you'd WANT to screw up to end it.
Checking a chamber isn't a terrible, rote, chore. And you don't have to do it nonstop till the end of days. If it's too much of a chore, all you have to do is not pick up the gun in the first place.
So in your example, if you got bored of picking up quarters, all you'd have to do is get up from the table and do something else that has nothing to do with quarters.
Some people have to handle guns daily, perhaps even under stress and/or distractions, whether they want to or not. Some are cut out for it. Some aren't. And there's also the fact that no matter how much you like something, once you do it for a living it becomes a chore. But the rest of us can choose when and how we handle firearms. Yes, some of us will make bad choices.
One in particular showed that if you check your chamber a few thousand times and it is empty your mind gets trained to see it empty.
First of all, I bet this study they do the chamber check 3000 times in a row. IOW, in a rote, meaningless fashion that has nothing to do with most of our real worlds. That is, unless it's your job to chamber check a pile of 3000 weapons where you have no personal responsibility for what happens if you screw up.
Most firearms owners may not even chamber check a weapon that many times in our lifetime. And that figure will be stretched over a lifetime, not one day in an artificial environment.
When you get to the point where you are just going through the motions, it's time to stop handling firearms.
I was at a match where this young nub raced to show clear at the end of each stage.* I don't know whether he was an idiot and thought that it was part of his time. Or whether he was an even bigger idiot and thought it looked cool. When you unload a gun, you have all the time in the world.
*He also got called for "trigger" twice. Scary thing was an old fella ran around with his finger on the trigger of his 1911, twice, and no one called him for it.