The old have duties to the young too. The claims are not absolute. If labour becomes scarce, or working conditions harsh, housing short, the burden of fulfilling them [producing the food, heating, housing, entertainment, care] is greater.

Older generations hv broken contract by not contributing enough, retiring too early, on higher pensions, while stifling productivity (housing, Brexit, invest. in infrastructure). Meanwhile the young face record high tax rates, housing costs, negative savings, low pensions & will work longer for less

The old will feel this in the prices they pay in the market for everything they need. A poorly functioning society will generate less in return for the value of the claims the old have built up.

Or just the old start living (much) longer than they did when the system was designed ...