A 7% average return would require more exposure to volatile assets (like equities) than is prudent for those investing for over a potentially short time like retirement. One must also consider morbidity risk, currency risk and interest rate risk.

I think it is most prudent for non-investing professionals who want to live this life to buy two annuities, one denominated in the currency of their home country and the other denominated in the currency of their new country.