In college I had a friend who didn't even bother locking his door and always left his keys in his car and it was never a problem.
The first part of your post is pure hyperbole. There are plenty of places less crime ridden then Baltimore or Detroit where you absolutely have to lock your things or they are likely to get stolen. Pretty much any urban area in the US. Most suburbs as well if you park on the street. Kids will go down and just try doors. They have no intent of picking anything or forcible entry, just snatching the low hanging fruit.
I have lived in northwestern Nebraska so I get it, there are places where you don’t have to ever lock your door.. that is the exception.
To counter your friend: I lived in one of the lowest crime rate suburbs in the US. Stupidly left my door unlocked in an apartment parking lot overnight.. everything of value was cleaned out in the morning.
An inmate advised me that I should just leave that pass on the windshield at all times - as it would be more effective against theft than any immobiliser.
I did leave it in place, and a few months later, just about every car parked curbside down my street had had its stereo and valuables snatched - except mine.
Now, obviously, this may have been a result of my stereo being pretty basic, though of recent manufacture from a renowned brand - but I like to think it was because of the visitor's service pass.
That being said, a lock has to be just good enough to deter theft. In my area, that's means a simple door lock for houses and a U-lock for bicycles. In other areas, you need far more security. But to goal isn't to keep out a determined attacker, but to make it more worthwhile for the thief to move on to the next house/car/bike than to try to get past your lock.
If they break in you still have to pay to repair the damage and the things they've taken.
I'm fairly certain, if someone broke into my house, the biggest bill would be repairs, not replacements.
But more than you'd think. Criminals are aware that they can often be in a different state before the police arrive at a rural crime scene, reducing the chance of getting caught.
