We have a bad experience with this PoS principle in France. It ended in a revolution. The assumption that people with the most stakes will act in the interest

We have a bad experience with this PoS principle in France. It ended in a revolution. The assumption that people with the most stakes will act in the interest of the community has been proven flawed in many occasions. They will act in their own interest first whatever it wight be. The weak logical link is that their own interest always coincide with the interest of the community. If someone could explain me how this assumption will always be true, I would be very happy.