The United States promoted globalization, and the United States ended the process of globalization.
Globalisation in itself wouldn't be as bad, if the profits were equally distributed. But most often globalisation just means taking away worker and consumers protections so mega corporations can outsource manufacturing/labour/services to cheaper countries with low or no environmental / social protections. Before Globalisation of markets there must be a globalization of citizen rights to the highest standards.
Then the disadvantage of scale slowly becomes clear: this concentrates wealth and power in less and less, and eventually one, location. This is how Rome, Paris, London and, outside of the US, Teheran and Beijing are not just a bit bigger than the cities around them but completely outclass them on every metric. Even within those cities it's not exactly equally divided. The amount of wealth in the City of London is more than all the rest of London combined.
Of course, as Ireland and Scotland can explain, by then the exit is closed.
"Wealth" is nothing but debt, mostly from people living in the further away parts of the empire. That's why a poor person from middle America is tending the golf course in Florida. One problem with that, is that debt is a fiction. Someone strikes a few lines in a law book, and debt is gone. For people living far away from the power centers that sounds better and better.
The US hasn't had enough time yet, and on top of that, it is the hub of the world in many ways. Mostly because in WW2 the rest of the world decided to destroy itself, leaving the US as the only intact industrial power, and thus lots of debt is being created in the world and brought to the US to build stuff. Technology, internet, military, financial, ... plus the power centers in the US haven't (fully) merged yet. It will come.
The bigger the empire, the less equal it is for the people living inside it.
Empires collapse because large parts of the empire are plundered of all economic value they can generate, in trade for wealth in the power centers, after which most of the empire becomes a resource sink ... and that is not something the military can fix. But by then the power centers have depended on wealth being brought in to them for decades, sometimes centuries ... and more and more they have to care for themselves. A lot more work, done by the locals, must be done for less in return. For one thing, the power centers must militarily defend the heartland ... and at this point, must do so while getting nothing in return.
Here's a funny (but meant very seriously) illustration of the end and if you think about it, terrible, article about China's southern border asking the questions: WHY would China defend this border? HOW would China defend this border? WITH WHAT would China defend this border? Illustrating the problem. Read it now because this will become crisis #1223, at which point this subject will become yet another target of CCP censorship. And it's not like the US or Russia, or India, or Europe don't have the same problem.
https://www.scmp.com/economy/china-economy/article/3287769/c...