The world economic system may be related to something like the euro, although that seems to be fragmenting because of political divisions. If the people around the world are expected to fall into line under global leadership then there has to be a global problem to solve, that can only be solved at the global level. Climate change seems like the obvious candidate, especially since it carries many features of a global religion already.
People won't naturally fall into line and follow ever-more leaders. But if there's a problem that needs to be solved, especially one that creates the sense of alienation directed at those who even dare to question whether it's a problem at all, the combination of wanting to be a part of the solution and not wanting the social exclusion associated with doubting or denying, sees people fall into line very happily. Just look how many problems have proposed solutions that begin with "introduce a new tax on..." and people line up to express approval of how it's the right way to go. It won't be long before those new taxes are global.
Then look at the growing outrage at companies like Google, Amazon, Starbucks etc and their tax avoidance schemes. They pay every penny of tax that is legally due, they just use wrinkles in tax laws in different countries to minimise the amount they actually pay. According to one report I read Google was reckoned to have legally avoided something like $3,700,000,000 in taxes in 2017 alone by clever accounting schemes. How to stop such things, and force the corporate behemoths to "pay their fair share"? The solution has to be global because as soon as any one nation does something else another wrinkle will exist. So it's not all that far-fetched to see how combinations of economic hopelessness, paired with growing anger at corporate behemoths, will encourage people to support global governance even if only in the hope of forcing the corporate giants to play by the same rules as everyone else. It won't work, of course, but people will stand in line to demand it and in the process subject themselves to another layer of governance. If one-world government does come, I suspect the mark of the beast will follow relatively shortly afterwards.