> Then make the fines 50x more costly. Put them out of business. Anyone else would go to prison for life.

That is over simplifying the situation.

First, you cannot just arbitrarily x50 the fines. That would put the bank out of business. You cannot jeopardize a whole business (and the customers savings) just for the behavior of some bad actors. The fine should be at an appropriate level to trigger strong incentives for the existence of a reasonable compliance layer.

Second, the relationship between the severity of the punishment and the crime rate is definitely non linear.

i.e. even at the highest possible severity (say, death penalty) there will be crimes committed. This has been demonstrated over and over again.

There is a number of reasons for this, but I think the most compelling is that crime is often not a well thought out plan, it's a slope.

Imagine the following situation:

You're walking in an empty street and spot a truck loading MacBooks from an Apple store. Truck looks legit, workers wear Apple uniforms. Upon looking at the guy filling the truck, he charmingly smiles back at you and explains that they are sending back last year models for refurbishing, and hands you one of the boxes saying "here mate, half of these will be recycled anyway".

That's what bribery in the real life look like. It happens in broad daylight, and with just enough credibility that your brain will try very hard to convince your rational self that the "good luck" is not illegal. It also places you in a situation where you have to give an answer quickly, during a potentially stressful or socially awkward situation.

If you read this from your office chair, it seems completely obvious that the guys are robbing an Apple store. And handing you a free MacBook in the process is really shady. After this gift accepted, it will be much harder for you to be 100% honest with a policeman asking questions on what happened.

But when placed in the real situation, your brain will try very hard to convince you that an abnormal situation is surely normal. The social anxiety of refusing the MacBook may also lead you to accept it without thinking, because you don't want the other person to think you believe they are robbers. You may also see some other people receiving the MacBooks too and that may reinforce the feeling that this is normal.

Bribery is all about the gentle slope of deviances. You will deal with people from respectable companies, with a good title. It will start with a lunch that they insist to pay, then it will be a good bottle of wine sent for christmas (how mindful), then a small irregularity in the account will be discussed over dinner in a fancy restaurant, you will be flattered to have such a good relationship with your client. You will feel like you're important and it's just the way business works in the high spheres. Next thing you know you will think you're some kind of entrepreneur doing business with them without necessarily really understanding what they are doing.

That slope is the very reason compliance rules often start at ridiculously low numbers. Most bankers with a reasonably actionable position will have a 6 figure salary. Yet the compliance rules will prevent any kind of gift higher than $50. You will definitely not bribe anyone with 50$, but it's enough to kickstart a slope of "I pay the restaurant bill, it's no big deal we don't count between us right?"

All in all, I'm not saying bribery is acceptable or anything like that. I just want to emphasize that when placed in certain situations of stress, social anxiety, etc, entering the "crime slope" may happen without the actor really having the time to make a rational, well thought out decision.