>This is an impossible scenario because there is no authority that can enforce this.
No, it's not impossible, it's just not extant. It may be true that there is no path from where we are now to that world, and it is certainly true that if there is a path it's not trivially predictable. But this can be said of the "one world government" thing as well. Knowing that people like myself exist and would sabotage attempts at one world government, how do you propose to make that possible?
>We had what you wanted in our tribal past,
No, we had something even better. We had a zero-world-government. That truly is impossible, at least considering that I'm not a fan of human extinction.
It's impossible in the sense of "this goes against an informed understand of history and human nature", which admittedly is a soft analysis not rooted in verifiable fact, but is one that I nevertheless hold to. The last 10,000 years have been a gradual, unceasing trend of increasing centralization, from isolated hunter gatherer tribes, to EU and UN type bodies today. The unceasing nature of this trend isn't an accident. There are underlying causal factors that generate it. Positing that those causal factors will continue in the future, leading to an increase in the size of EU-like entities, to the point of de facto hemispheric/world government type bodies, isn't so radical, even if it is uncertain.
>It's impossible in the sense of "this goes against an informed understand of history and human nature",
No, that's just your narrative. You even acknowledge that there was a point in history where it was the prevailing condition, so clearly it wasn't against human nature.
> The last 10,000 years have been a gradual, unceasing trend of increasing centralization,
Hardly gradual. Incredibly punctuated. In some places in the world the stateless/tribal paradigm survived until modern times. The progressive's version of "the market only ever goes up!"...
>Positing that those causal factors will continue in the future,
So you're bad at prediction too. No, humanity becomes extinct in the next 2 or 3 centuries, because you've all become sterile worker drones and can't even maintain a stable population. Sometimes I hope that part's just an accident, but then I read words written by people like yourself, and you seem all too enthusiastic about it as if you've discovered some divine secret. Oh well.