The only thing that might incentivize people to think about the long term is getting rid of all old age benefits (including continuous bail outs of broad market assets by the federal government by sacrificing the purchasing power of the currency).
Right now, we take productivity from people who sacrifice to raise kids well and give it to those who don’t raise kids well, or not have them at all.
This obviously leads to an arbitrage opportunity (as evidenced by DINK lifestyles).
I do not see any other way other than to remove this arbitrage opportunity. Which probably will not happen in any democracy due to old people’s voting power.