The pension ponzi scheme has to end sometime. Whether the music stops when it's my turn, yours, or today's children it simply isn't possible to grow the number of people paying in forever.
Fact of the matter is: you're going to have to support the old, less able people, whether you want it or not. You don't get to just not pay for it, not at any kind of a macro scale.
OTOH if the population isn't growing and economy is contracting as a result, you could find yourself paying a lot more than you do now. Like, potentially, several times the amount.
