For those who are still not sure what a nation-state is and why it is collapsing:

The nation-state ‘ s model of statecraft  links the sovereignty of a state to its territorial borders. Within these borders a state is supreme with respect to its law, and beyond its borders a state earns the right of recognition and intercourse to the extent that it can defend its borders. (Philip Bobbitt )

No state can defend its borders from terrorists, international corporations, and cyber hackers. And all intents to guard the borders against migrant flows are failing, too. No borders = no nation-state. The global economy spits on borders. Hence, there can be no more nation-state.