A Private Problem?

It seems that all the problems that traditional systems of retirement face is that they are affected by long-term shifts in the population because the young pay for the old to live.  When the young form too small of a proportion of the population in relation to the old, systems of this sort simply cannot continue to exist indefinitely in free societies because at some point the young will decide that economic conditions are too harsh and they will emigrate from the country.

The money taken from the young also prevents them from investing in their own retirement accounts, which sets the stage for future financial dependence and instability.  In short, the problem with current systems of retirement is that the elderly have to rely on younger workers to pay for their retirement.  In an ideal world, individual workers would invest their earnings in a retirement account.  This account would grow over the years, to the point of being sufficient to fund retirement.
Programs like social security, while they are certainly necessary for people who are incapable of providing for themselves, are simply not viable as a means of support for retirement for the whole population.  The optimal solution for the general population to save individual retirement accounts from a young age, with social security acting in its intended role- as a safety net to guard against unexpected disaster, and not as a retirement plan.  Such a plan would be difficult to implement, however, because so many people have already come to rely on programs like social security to care for them in their old age.