Sovereign governments and nations are simply organizations exercising and reflecting the will of people for self-governance, within a criterion of democracy. Sovereignty for others may mean living in a subjective state as something like a captive or prisoner of an elite or authority.
A country is a word; a name, and abstract concept more or less equivalent to the word domain. Domain etymologically was from the Latin word dominus, meaning ‘Lord’. In my opinion the world shall have sovereign peoples of some form or other even against the jejune paradigm of one world government as the governance-for-others sought after by leftists, communists, socialist, dictators oddball religions and megalomaniacs of all sorts.
Economic powers with instant telecommunications tend to evolve plutocracy rather than democracy, since there are advantaged capitalists and elites able to lever the abstract tools to buy everything and to finesse the world’s billions to work for them. The power of elite wealth to end self-determination by national democracies is a clear and present evolving situation. Already it is difficult to imagine the reform of capitalism toward a new ecological sustainability foundation as crass materialism made popular by the social and broadcast media drives the billions of souls toward consumerism and blind allegiance to the succor of globalism under plutocrats and communist elites.
In the future social dynamics will tend to disrupt the constant political thermodynamics of stable power structures as they have over history, even as history evolved political forms and technology concurrently. Reorganization of a global state, that should be avoided to start with, would tend to be a greater disaster than managed. local troubles. Firewalls within a structure exist for a reason though some would like to remove them, and other remove them as obstructions to wealth development.
As humanity moves off-world sovereign powers may return to be the normal condition as self-reliance and cohesive organization of millions of souls wold be requisite with other authorities possibly light years distant. There are some very strong and beneficial points to local and sustainable democratic self-reliance that are lost in a globally homogeneous culture.