Disagree.
Counter-examples:
401k in the US
Second pillar in Switzerland.
The money comes from the people saving and investing their own money for their old age.
Shocker, I know.
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.
This change in retirement age only partially applies to those who started working before 1995. Therefore, it is still in a transition phase, and it will take some time before it takes full effect.