I don't disagree with what you said in principle, but I really do think the solution is raising the retirement age. Whether it's age 70 or not, one can quibble over that, but if we look toward increasing it—I shouldn't have said the retirement age, I should have said the pensionable age, because you can retire when you want, just fund it yourself—the pensionable age is critical.
I don't think most people would argue that western Europe is a socially unjust part of the world. They're moving very strongly across Europe towards age 67 or 68, and they're talking about going to age 70. I think that would wash away or deal with a lot of the sustainability issues, as well as the fairness issues, if you had one common pensionable age at which you could draw a pension.