And if you’re an American, the prospect of that single national government being say Bangladesh (https://www.nytimes.com/2017/05/26/world/asia/bangladesh-sta...) should be pretty scary! Star Trek style global government seems attractive to many people because they assume it’ll be “America in Space.”
Still, I don't think we can face planetary-scale challenges much longer as a bunch of competing nations; some form of global governance will be necessary for humanity to move forward.
As for culture difference, this may be unpopular opinion, but I do hope things will homogenize further over time. The driving aspect towards cultural unification even today is that people copy what works.
https://en.wikipedia.org/wiki/Socialism_(disambiguation) https://en.wikipedia.org/wiki/Social_democracy
Yeah a "Great Leap Forward" kind of moving forward for humanity? Sounds good, works bad. Capitalism looks bad, but works good. I once also wanted a kind of world government but as I grew more knowledgable this Idea really started to terrify me. A decentralized world of competing small units with a small set of (trade) rules seems like the best option mid- to long-term. In short term of course socialist type of governance gives stability. Just 2 cents from a fellow European
If you assume that the world order should look like America in charge, everyone else playing quietly in their own garden then everything is fine. If you assume that the Asian, African and European powers might see the world differently, there is a lot of potential that the last 60 years are not the inevitable tide of history but a happy anomaly while everyone stood back up from WWII.
[0] http://blogs.reuters.com/anatole-kaletsky/2014/06/27/world-w...