Sure, looking backwards. But we appear to be on the cusp of a "seachange".... US equity valuations are historically crazy high. And this note is in context of capital preservation for "mature" portfolios. Diversification is warranted. Just an opinion,
There's also the arguement for diversification. It doesn't have to be more than 5% of a portfolio. One thing I'd look at is the rate of foreign taxes on those dividends. Is might be higher than the tax rate on US holdings.