I have an answer different from the others.

US economy depends on the US intellectual property system, a few US monopolist companies and the US dollar, and the financial system.

Especially the intellectual property system. However different laws can be in various countries, in fact everybody tries to follow US law.

It means that a lot of things produces elsewhere mean royalties to US companies, and a lot of things can’t be produced without permission, control of markets, planned development of microelectronics and tech in particular, yadda-yadda.

So - if, in some hypothetical situation, that IP system is undone, with some countries having similar laws, some more like USSR’s “public domain by default with some fixed payment to patent holders”, and all the intermediate variants, then you’ll just have a second depression. Because a huge part of the economy will shrink.

US foreign debt is a meme subject, but honestly, if USD stops being the world’s most reliable currency, you’ll also probably have a default.

US actual industrial production (what doesn’t shrink as easily) is not so impressive when looking at its size. A lot about US level of life doesn’t really match the efficiency of the economy. Say, if you look at Germany, life there is very different. In some ways better, maybe, but many things normal in the US are not achievable there.

My point is - the American IP laws were spread around by pressure. Not just that, but sometimes the monopoly roles of American companies. Part of that pressure is the military guarantor role.

If that stops being relevant, a lot of things which were a given for your economy for many years will stop existing. And for a few other economies too. It might not look as bad as the USSR’s collapse, but it will probably look as ruined and unpredictable as the 1960s world.