it is a common misconception that how the retirement is funded makes a huge difference in how much you need to save. In most situations, it does not matter nearly as much as people believe. Dependency ratio will determine in large part how much people will need to save to get a given level of retirement income.

For example, your 401k ability to pay for your retirement will depend on productivity gains , growth, saving, investments happen in the future. Those will look very different if you have 4 working age people for one non working person, vs 2 working age people for one non working one. In the extreme case, if nobody is working anymore when you retire, your 401k will likely worth almost nothing.

The problem in France is not how it s funded, but the fact that retirement incomes are way above the funding level. France, with Italy, are the only two OECD countries where retirees have a higher income that working people, which is insane. However, since retirees vote much more than other demographics, their too large income will not be touched.