I'll indulge your straw man because it's actually pretty good at illustrating my point. 99.9% of people are not psychopaths. But you only need .1% of people to be psychopaths. In a world where you get $5 and no threat of prosecution for stabbing people, you can bet that there will be extremely efficient and effective stabbing companies run by those psychopaths. Even normal people who don't like stabbing others would see the psychopaths getting rich and think to themselves "well, everyone's getting stabbed anyway, I might as well make some money too". That's what a race to the bottom is.

And that's why the government regulates stabbing.

In the behavioral science (of which economics should be a sub-field of) this is called perverse intensives. A core-feature of capitalism, is that if you don‘t abandon your morals and maximize your profits at somebody else’s expense, you will soon be out-competed by those who will.