You may misunderstand how the "entire world" thinks about it.
I'm French and live in Hong Kong so I'm exposed to a lot of European and Asian real estate experience, have friends with everything from a villa in Vietnam to a flat in Berlin etc.
So the way we see the US is:
- it's risky to live there, for many reasons (high crime, gun ownership, children mass murders, rampant untreated schizophrenia, drug abuse issues)
- it's optimized for gasoline consumption, you can't really live near your work as much as elsewhere, the city center isn't as interesting as in Asia/Europe and suburbs are very low-density, copy-pasted houses, so the "value" of a property is more flimsy than other places.
- it's expensive with low speculative upside: it's a very mature market, it might conserve some value but it won't like double like in Saigon, Bangkok or Lisbon, and it won't "last forever" like Paris or Hong Kong who have structural reasons to be expensive (Paris as capital of a European geographical center between 6 rich countries, Hong Kong as a gateway in and out of China). To give you a random example: Seattle is quite "new" and particularly useless / unknown to, say, a successful Tokyo upstart. It's considerably more expensive than what it should be from an Asian point of view.
- Visas are annoyingly complex vs very open economies (in term of real estate investment) and the US is far down the ranking of countries you trust to access your property easily. I'd rather have a small thing in Singapore that I know I'll always be welcome to visit, than something huge in Ohio which will make me feel like shit each time I have to fill paperwork to see.
- Political instability seems to have taken hold and we never know if foreigners will be barred from the US on a whim because of some flu. It doesn't feel that much better than China, which is considered one of the worst market to invest in around me (basically you have random chances to simply see your house unreachable for years there, or disappear).
I feel "the rest of the world" considers the US as average, not too dangerous but not too profitable to invest in. Most of my friends are very wary of investing there. I would never myself. All these may be factually wrong btw, this is just how I hear the market talks around me, in the rest of the world: the US "brand" is not very popular, is all.