Dependent is a strong word. If the USA disappeared tomorrow, the rest of the world would reorganise quickly enough; the global economy would settle into a new normal within a few years.
I'd go out on a limb and assert that if China disappeared tomorrow, the consequences to the world economy would be far more devastating. So much of the global economy is tied—directly or indirectly—to Chinese manufacturing. It would take multiple decades for the world to replace the supply chains and highly skilled labour.
It would not be normal in a few years. The US is also a very large manufacturer, much of which is in more "essential" goods such as large equipment. Individuals and governments across the world hold US treasuries, so the US disappearing would wipe out trillions of dollars of assets. The US currency is a common reserve currency across the world, and would become worthless, creating a massive domino effect in banking across the world. Many important internet services would no longer function. Countries like Japan and Israel which rely on the US for defense would suddenly face a decrease quality of life and even existential threats. The countries which rely on US aid would suffer greatly.
Is the world dependent on the US? No, you're right that dependent is a very strong word. However, the US, for better or worse, provides a very high amount of global stability. The US has a massive economy and a very strong military, and the world would be very different if any country like that were to fail.
While losing China would certain set off shockwaves, I'd say you are in fact on a limb and have it backwards. Manufacturing can be moved and trivially ramped over a few years, perhaps at great cost, but still, only cost. Advanced technology, culture, and other elite exports are not so easily moved to Bangladesh or Vietnam. I'll go out on a limb and say losing Japan would be a bigger loss for the world than losing China due to this. Things I own that are made in China, or have parts made in China, are mostly owned for the cheaper price, not for any uniqueness. Japan and the USA export unique things which cannot be replaced by merely paying a higher price. Losing Google alone would set the world years back. Losing America would scramble world culture entirely (maybe for the better, you say, but that's a value judgement). Whereas China is so insular, the world would move on quickly.
"There's a confusion about China. The popular conception is that companies come to China because of low labor cost. I'm not sure what part of China they go to but the truth is China stopped being the low labor cost country many years ago. And that is not the reason to come to China from a supply point of view. The reason is because of the skill, and the quantity of skill in one location and the type of skill it is."
"The products we do require really advanced tooling, and the precision that you have to have, the tooling and working with the materials that we do are state of the art. And the tooling skill is very deep here. In the US you could have a meeting of tooling engineers and I'm not sure we could fill the room. In China you could fill multiple football fields."
I'd go out on a limb and assert that if China disappeared tomorrow, the consequences to the world economy would be far more devastating. So much of the global economy is tied—directly or indirectly—to Chinese manufacturing. It would take multiple decades for the world to replace the supply chains and highly skilled labour.