It's not. The system is overpopulated. Lets say the system can hold "x" amount of people, then anything x+1 will either be a growing parallel system or internal pressure will cause a system failure. It's not possible for two existential systems to occupy the same space. It's like one person can't exist inside another, well except during pregnancy or some fucked up mutation, which all end up either in expulsion of a person or suffering\death of both subjects. Any system must maintain it's optimal load. Even if it overloads for some reason, it must return to normal state unless it wants to stop functioning completely.
Nobody is going to allow the people who will not fit into current system to go somewhere and form their own system, because of resource scarcity.