What happens when the gangs write the laws?
That would never really work because the gang tends to abuse smaller minorities. This is the difference between a gang system and one where law exists.
Gang tends to be mobs, they abuse smaller groups or individuals that do not agree with their opinions.
And eventually you will be a minority in at least one of the ways you think, because we all think differently.
Also, the masses tend to be stupid. And allot. Most % of the population is not composed by brilliant intelligent people, but the opposite.
Do you want idiots making rules?