[potato3732842]

There's no fundamental reason that we can't save for retirement in a world with a roughly static population.

What we can't do is continue to use pyramid scheme math. Everyone more or less needs to set aside their own surplus for retirement over the course of their lives. Of course this gets financialized away such that the current workers pay the current retirees and whatnot but the math still holds. Basically at scale average people's entire lives can no longer be run based on net neutral or net debt with reliance upon market growth to have surplus available to spend at the end of it. We'll have to run a surplus and set some aside.