Ultimately, the goods and services consumed by retirees are provided by the real economy, not by financial instruments (which is just a fancy way of saying that you can't eat savings).
The way to ensure their availability is to make real investments, not financial ones: build infrastructure, factories, accessible retirement homes; train nurses, doctors, etc...
Unfortunately, focus on the financial can trigger (and arguably has already triggered) some extremely counterproductive reflexes. For example, we've been told for decades now that private savings are essential for retirement. This may be true at an individual level, but in the aggregate it causes a savings glut - those low interest rates aren't just the making of central banks - and it withdraws effective demand from the real economy, which disincentives many of the investments in the real economy we need to provide for an aging society.
So yeah, good to see some focus on the aging society, but please try to look beyond the financial smokescreen.