What a lot of hooey. What happens if interest is banned, or abandoned? You don't get to buy a house, you rent all your life, probably to the profit of those wealthy guys you despise, and end up with no wealth to see you through your retirement. If you're lucky enough to find a job it will likely be with a giant corporation, the small business that might have hired you never got off the ground because they couldn't borrow the needed funds...and you know how nice a lot of the giant corps are. You don't like banks? I don't either which is why I have always dealt with my credit union, a non-profit entity instead.

Your island analogy is fundamentally flawed. Nobody outside of your family and perhaps some social safety net program gives you a stake in life, certainly no gangster equivalent, In most cases your family won't demand the money back, certainly the safety net program won't.