[samjmck]

Isn't that only a problem if you are only invested in the US? There exists ETFs that are invested in multiple developed countries, such as index funds that track the MSCI World.

[rr808]

Yes. After continued under performance of non-US markets, not many people have a significant exposure to those places.

[malfist]

Are you sure about that? The standard boglehead portfolio has ~1/3 of stock holdings in non-us funds.