That only exacerbates the fundamental problem: smaller working cohort, larger dependant cohort.
Resource consumption per capita of youth is less than elderly (especially healthcare), and generally reduces with time (excepting education). Youth lasts only 15-20 years before gainful employment can begin. Old age stretches from 65 onwards. Early retirees may spend 50 years or more "retired".
Which with average life expectancy is close to 15-20 years of remaining life. E.g tons don't make it to 70 even.
>Early retirees may spend 50 years or more "retired"
Early retirees are usually people who saved money / hit the business jackpot, not people who expect some others to work to pay them a pension.
We're also forgetting that (at least in civilized pension systems) retirees at 65 had 30-40 years of paying taxes (along with the employers part) for their pension scheme.
Resource consumption per capita of youth is less than elderly (especially healthcare), and generally reduces with time (excepting education). Youth lasts only 15-20 years before gainful employment can begin. Old age stretches from 65 onwards. Early retirees may spend 50 years or more "retired".