You make it sound like holding a US-only portfolio is a new phenomenon that people are finally choosing. When I first invested in index funds, there were no int'l equity index funds available to retail investors in the US. We are fortunate today to have low cost implementations of any asset class that an individual investor should need.abuss368 wrote: Not really. The beauty and simplicity of Jack Bogle’s Two Fund Portfolio is Total Stock and Total Bond. Many Bogleheads are learning that the portfolio will never be below average and are choosing to simplify. It is an encouraging trend.
Over the last 30 years, the trend has been toward more diversification, not less. You can be successful with a US-only portfolio. Vanguard's position is that a US investor should have at least 20% non-US equity. This is a determination not by one person, but by a large organization filled with investment professionals and economists. It is not just Vanguard. Can you find a single target date fund that holds exclusively US equities? Can you find a 401K plan that lacks non-US equity funds? If there is a trend to hold US-only portfolios, nobody has notified the mutual fund and retirement plan industries of that yet.
I have a lot of sentiment for a US-only portfolio. I don't hold non-US bonds. Non-US equities are only 25% of my equity holdings. I won't be happy if things turn out badly for US equities. But if nothing else, Covid has demonstrated how much uncertainty there is in the future. Globalization is still a major force of change in the world with an uncertain outcome. And the unprecedented interventions in economies around the world by central banks is new territory. There is no playbook for how things will unfold in the future.